The statement that is true is that pressure always increases when force increases or the area acted on decreases (option B).
What is pressure?Pressure is the amount of force that is applied over a given area divided by the size of this area.
The pressure applied to a surface can be calculated by dividing the force required by the area of the surface as follows:
P = F/A
The above shows that the pressure of a body is inversely proportional to the area but directly proportional to the force.
This means that as the pressure of an object increases, the force increases while the area acted on decreases.
Learn more about pressure at: https://brainly.com/question/945436
#SPJ1
What is the mass of a 37.0 Nweight?m =?] kgEnter
Answer:
m = 3.8 kg
Explanation:
The weight can be calculated as follows:
[tex]W=m\cdot g[/tex]Where m is the mass and g is the gravity. So, replacing the weight by 37 N and the gravity by 9.8 m/s², we get:
[tex]37\text{ N = m}\cdot9.8m/s^2[/tex]So, solving for m, we get:
[tex]\begin{gathered} \frac{37}{9.8}=\frac{m\cdot9.8}{9.8} \\ 3.8\operatorname{kg}\text{ = m} \end{gathered}[/tex]Therefore, the answer is m = 3.8 kg
Which statement below best describes how scientists explain gravity's role in the formation of
our Solar System? and Why?
A. The combined gravitational attraction between our planets was so large that it pulled the
Sun away from a nearby star cluster into the center of our Solar System.
B.The eight planets in our Solar System were originally orbiting a nearby star, and the Sun's
gravity was large enough to pull those planets into orbit around the Sun.
C. Due to the expansion of neighboring solar systems, the gravitational attraction of our
planets to those solar systems forced the formation of the planets around our Sun.
D.As the Sun was forming, the force of gravity caused surrounding dust grains to collide and
stick together, forming dust granules into increasingly larger bodies that became planets.
D. As the Sun was forming, the force of gravity caused surrounding dust grains to collide and stick together, forming dust granules into increasingly larger bodies that became planets.
About 4.6 billion years ago, the Solar System was a cloud of dust and gas known as the Solar Nebula.
The gravitational forces of the planets push gases out of their atmospheres and form a star at the center of the solar system.Gravity compresses the gases in the center of the solar nebula until temperatures are high enough for nuclear fusion to occur.It collapsed the material in on itself as it began to rotate, forming the sun at the center of the nebula.As the sun rose, the remaining material began to clump together.Gravity is the force that pulls a body toward the center of the Earth or any other physical body that has mass.
Therefore "As the Sun was forming, the force of gravity caused surrounding dust grains to collide and stick together, forming dust granules into increasingly larger bodies that became planets", best describes scientists explain gravity's role in the formation of our Solar System.
To know more about gravity,
https://brainly.com/question/3507355
#SPJ1
Set the cannon to have an initial speed of 25 m/s. For which situation do you think the cannon ball will be in the air for the longest time: if it is set at a 25-degree angle, or if it is set at a 35-degree angle?
Question 5 options:
25 degree
35 degree
The cannon ball will travel the highest distance when the angle of projection is 35 degrees.
What is the maximum height of a projectile?The maximum height reached by a projectile is calculated using the following formula.
H = u²sin²θ/2g
where;
u is the initial velocity of the projectile θ is the angle of pojectiong is acceleration due to gravitywhen the angle of projection is 25 degrees;
H = (25² (sin 25)²) / (2 x 9.8)
H = 5.7 m
when the angle of projection is 35 degrees;
H = (25² (sin 35)²) / (2 x 9.8)
H = 10.5 m
Thus, the cannon ball will travel the highest distance when the angle of projection is 35 degrees.
Learn more about maximum height here: https://brainly.com/question/12446886
#SPJ1
Which of the Figures correctly represents the force diagram to solve the problem?
ANSWER
Figure 1
EXPLANATION
We want to identify the correct force diagram acting on the object on the inclined plane.
When an object is moving on an inclined plane, there are four forces acting on it:
1. Friction force, Fr
2. Normal force, FN
3. Component of weight acting parallel to the inclined plane = Wsinθ
4. Component of weight acting perpendicular to the inclined plane = Wcosθ
Therefore, the correct option is Figure 1.
A converging lens has a focal point of 3.93 cm. If you place an apple 19.24 cm away from the lens, where would the image be formed? Submit your answer in meter.
Given
The focal length , f=3.93 cm
The object distance, u=-19.24cm
To find
The image distance
Explanation
By lens formula we have,
[tex]\begin{gathered} \frac{1}{v}-\frac{1}{u}=\frac{1}{f} \\ \Rightarrow\frac{1}{v}-\frac{1}{(-19.24)}=\frac{1}{3.93} \\ \Rightarrow\frac{1}{v}=0.202 \\ \Rightarrow v=4.95cm=0.0495\text{ m} \end{gathered}[/tex]Conclusion
The image distance is 0.0495 m
Which of the following examples is NOT an example of energy transfer?bringing water to a boilba boat being accelerated by the force of the enginecrain falling from a clouddwaves in the ocean
Rain falling from a cloud is not an example of energy transfer.
. In one day, the temperatures of a desert range from 110°F in the afternoon to 55°F at night. What
is this temperature range on the Kelvin scale?
Answer:
30.5555°K
Can be rounded to 30.56°K
Explanation:
The relationship between °C and °K is
°K = °C + 273.15
To convert °F to °K, first convert °F to °C and then add 273.15
°C = (°F - 32) x 5/9
So combining the two conversions we get
°K = (°F - 32) x 5/9 + 273.15
55°F = (55-32) x 5/9 + 273.15 = 285.9278°K
110°F = (110-32) x 5/9 + 273.15 = 316.4833°K
Temperature range in Kelvin scale
= 316.4833°K - 285.9278°K = 30.5555°K
What is the acceleration of a car,
moving along a straight line, that
increases its velocity from 0 to 15
m/s in 10 s?
Consider a house with a floor space of 200 m2and anaverage height of 3 m at sea level, where thestandard atmosphericpressure is 101.3 kPa.Initially the house is at a uniformtemperature of 10°C.Now the electric heater is turned on, andthe heater runs until the air temperature in the house risesto anaverage value of 22°C. Determine how much heat is absorbedby the air assuming some airescapes through the cracks asthe heated air in the house expands at constant pressure. Also,determine the cost of this heat if the unit cost of electricity inthat area is $0.075/kWh.
9038 kJ of heat is absorbed by the air assuming some air escapes through the cracks as the heated air in the house expands at constant pressure, and cost of this heat if the unit cost of electricity in that area is $0.075/kWh is $0.19.
What is pressure?In the physical sciences, pressure is defined as the perpendicular force per unit area or the stress at a point within a confined fluid.
A 42-pound box with a bottom area of 84 square inches will press down on a surface with a pressure equal to the force divided by the area over which it is applied, or half a pound per square inch.
The specific heat of air at room temperature is
[tex]C_p[/tex] = 1.007 kJ/kg⋅°C
The volume and mass of the air in the house are
V = Floor space × height
= (200 m² )(3m)
= 600 m ³
Mass = PV/RT
= [tex]\frac{(1013 kPa)(600 m^3 )}{(0287 kPa.m/kg.K)(10+273.15 K)}[/tex]
= 7479 kg
The amount of heat that must be transferred to the air in the house as it is heated from 10 to 22°C is calculated, taking into account that the pressure in the house remains constant during heating, as follows:
Q = [tex]mC_p[/tex] [tex](T_2 - T_1)[/tex]
= (747.9 kg)(1.007 kJ/kg⋅ °C)(22 – 10) °C
= 9038 kJ
Noting that 1 kWh = 3600 kJ, the cost of this electrical energy at a unit cost of $0.075/kWh is
Enegy Cost = (Energy used)(Unit cost of energy)
= (9038/3600 kWh)($0.075/kWh)
= $0.19
Learn more about pressure
https://brainly.com/question/945436
#SPJ9
Given 2 concentric wheels; what weight will an applied force FA of 40.0N down and tangent to the 18.0 cm radius wheel will balance an unknown weight tangent and down on the 10.0 cm radius wheel? Draw the situation
The given problem can be exemplified using the following diagram:
We will determine the magnitude of the force "F" that will balance the concentric wheels.
To do that we will add the torques produced by the forces. If the torque is counterclockwise we will set it a positive and if it is clockwise it will be negative.
[tex]T_{40}-T_F=0[/tex]Where:
[tex]\begin{gathered} T_{40}=\text{ torque produced by the 40 N force} \\ T_F=\text{ torque produced by the unknown force. } \end{gathered}[/tex]The sum of toques adds up to zero because we want to determine the force "F" when the system is in equilibrium.
Now, we substitute the formula for the torques:
[tex]F_{40}r_{18}-Fr_{10}=0[/tex]Where:
[tex]\begin{gathered} r_{18}=\text{ 18 cm radius} \\ r_{10}=\text{ 10 cm radius} \end{gathered}[/tex]Now, we solve for the force "F":
First, we will add "Fr10" to both sides:
[tex]F_{40}r_{18}=Fr_{10}[/tex]Now, we divide both sides by r10:
[tex]\frac{F_{40}r_{18}}{r_{10}}=F[/tex]Now, we plug in the values:
[tex]\frac{(40N)(18\operatorname{cm})}{10\operatorname{cm}}=F[/tex]Solving the operations:
[tex]72N=F[/tex]Therefore, the required force is 72N.
IfWhile shopping in England, Sally notices the cost of bananas is £2.10/kg. Sally isn't familiar with Great Britain Pounds (GBP) or kilograms, and needs to convert the unit price into dollars per pound. You may assume the conversion rate from dollars to GBP is $1 to £0.77, and there are 2.2lbs to 1kg. Round your answer to the nearest cent.
Each pound costs $1.2 in unit pricing.
Sally notes that the price of bananas in England is £2.10/kg.
Applying the exchange rate from dollars to British pounds (GBP), if $1 = £0.77, then £2.10 would be calculated as 2.10/0.77, or 2.72.
Using the pounds to kilograms conversion rate, 1 kilogram equals 2.2 pounds.
Consequently, the price per unit in dollars would be 2.72/2.2 = $1.236.
If we round to the nearest cent, the price per pound is $1.2.
To know more about currency’s exchange refer to https://brainly.com/question/2202418
#SPJ9
Jenny experiences an average downward force of 441 N anywhere she goes on Earth. Calculate her mass
Answer:
Given,
Force = 441 N
mass = ?
Keep in mind that acceleration due to gravity is constant 10m/s.
Force = mass × acceleration due to gravity
mass = Force / acceleration due to gravity
m = 411 N /10m/s
m = 41.1 kg
Therefore her Jenny mass is 41.1 kg.
Oil having a density of 924 kg/m? floats onwater. A rectangular block of wood 3.59 cmhigh and with a density of 975 kg/m° floatspartly in the oil and partly in the water. Theoil completely covers the block.How far below the interface between thetwo liquids is the bottom of the block?Answer in units of m.
A diagram of the given problem is the following:
To determine the distance "x" from the interface between the water and the oil of the block we need to add the forces that are acting on the system. We have the following:
Where:
[tex]\begin{gathered} F_b=\text{ force of the block} \\ F_w=\text{ force of the water} \\ F_{o\text{ }}=\text{ force of the oil} \end{gathered}[/tex]Since the system is in equilibrium this means that the total sum of forces adds up to zero:
[tex]F_b-F_w-F_0=0[/tex]Now, the force is the product of the pressure by the area, therefore, we have:
[tex]P_bA-P_wA-P_0A=0[/tex]We can cancel out the area:
[tex]P_b-P_w-P_0=0[/tex]The pressure is the hydrostatic pressure and is given by:
[tex]P=\rho gh[/tex]Where:
[tex]\begin{gathered} \rho=\text{ density} \\ g=\text{ acceleration of gravity} \\ h=\text{ height} \end{gathered}[/tex]Substituting in the equation we get:
[tex]\rho_bgh_b-\rho_wgh_w-\rho_ogh_0=0_{}[/tex]Now, we substitute the values of the heights according to the first diagram:
[tex]\rho_bgh_b-\rho_wgx-\rho_og(h_b-x)=0_{}[/tex]Now, we solve for "x". To do that we will apply the distributive property on the parenthesis:
[tex]\rho_bgh_b-\rho_wgx-\rho_ogh_b+\rho_ogx=0_{}[/tex]Now we associate terms according to the value of the height:
[tex]\rho_bgh_b-\rho_ogh_b-\rho_wgx+\rho_ogx=0_{}[/tex]Now, we take common factors:
[tex](\rho_b-\rho_o)gh_b+(-\rho_w+\rho_o)gx=0_{}[/tex]We can cancel out the gravity:
[tex](\rho_b-\rho_o)h_b+(-\rho_w+\rho_o)x=0_{}[/tex]Now, we bring the terms with the height of the block to the right side:
[tex](-\rho_w+\rho_o)x=-(\rho_b-\rho_o)h_b[/tex]Now, we divide both sides by the factor of "x":
[tex]x=-\frac{(\rho_b-\rho_o)}{(-\rho_w+\rho_o)}h_b[/tex]Now, we plug in the values:
[tex]x=-\frac{(975\frac{kg}{m^3}-924\frac{kg}{m^3})}{(-1000\frac{kg}{m^3}+924\frac{kg}{m^3})}(0.0359m^)[/tex]We converted the height of the block using the following conversion factor:
[tex]100cm=1m[/tex]Now, we solve the operations, we get:
[tex]x=0.024m[/tex]Therefore, the distance between the interface and the bottom of the block is 0.024 meters.
When light is reflected, the incident rays are bent and change direction.
Given
When light is reflected, the incident rays are bent and change direction
To find
Whether the given statement is true
Explanation
When we flash a light on the mirror, the light changes its direction and move in another way. So the incident light changes direction when reflected
Conclusion
The given statement is TRUE
I am not sure if this is true or false. Please help
We have the formula of Newton's second law
[tex]F=ma[/tex]Where F is the force, m is the mass and a is the acceleration.
If we isolate the acceleration
[tex]a=\frac{F}{m}[/tex]As we can see if the mass increases the acceleration will decrease
Therefore the answer is FALSE
How many hours would it take a plane to fly 1,500 miles if it was moving at a constant speed of 300 miles/hour? Include units!
Best answer gets brainliest!
Answer:
5 hours
Explanation:
distance/speed= time
1500/300= 5
What is the resistance (in Ω) of a 17.5 m long piece of 17 gauge copper wire having a 1.150 mm diameter?
In order to calculate the resistance of this wire, we can use the formula below:
[tex]R=\frac{\rho d}{A}[/tex]Where p is the resistivity, d is the length and A is the cross-sectional area of the wire.
The resistivity of the copper is 1.72 * 10^-8 ohms*m, so we have:
[tex]\begin{gathered} R=\frac{1.72\cdot10^{-8}\cdot17.5}{\frac{\pi\cdot(1.15\cdot10^{-3})^2}{4}}\\ \\ R=\frac{30.1\cdot10^{-8}\cdot4}{\pi\cdot1.3225\cdot10^{-6}}\\ \\ R=\frac{120.4\cdot10^{-8}}{4.1547563\cdot10^{-6}}\\ \\ R=28.98\cdot10^{-2}\text{ ohms}\\ \\ R=0.2898\text{ ohms} \end{gathered}[/tex]Can an object have a net negative charge of 2.00 x 10^-19
We will have that as long as the object is a conductor it will be able to have a net negative charge of 2.00*10^-9 C.
The oscilloscope can be used to measure AC frequency by counting the number of _____________ per unit time.A. PeaksB. Complete wavesC. ValleysD. Partial wavesJust please give me the answer, no explanation.
The oscilloscope can be used to measure AC frequency by counting the number of complete waves (Option B).
What is an oscilloscope?An oscilloscope is a tool used to measure voltage by observing how the electrical signals from different types of waves may change over a given unit or period of time, which is useful to monitor a client's heartbeat and brain waves.
Therefore, with this data, we can see that an oscilloscope is a device used to measure waves (in this case brain waves) in order to indicate a given outcome associated with electrical signals.
Learn more about the oscilloscope here:
https://brainly.com/question/10082422
#SPJ1
A. Thermal to Chemical to Electrical to MechanicalB. Mechanical to Chemical to Electrical to Thermal C. Electrical to Chemical to Mechanical to ThermalD. Chemical to Thermal to Mechanical to Electrical
Given:
Coal-fired power plant
Required:
Energy transformation in coal-fired power plant.
Explanation:
Coal has chemical energy.
When the coal is heated, the chemical energy transforms into thermal energy.
Thermal energy is used to rotate the blade of the turbine, so thermal energy transforms into mechanical energy.
The rotating blades produce electricity, so mechanical energy transforms into electrical energy.
Final Answer: The energy transformation of a coal-fired power plant is chemical to thermal to mechanical to electrical.
2. A saucepan containing 2 kg of water is heated. 400 kJ of energy is transferred. Calculate the temperature
increase of the water.
The specific heat capacity of water is 4200 J/kg °C. Give your answer to four significant figures.
The temperature increase of the 2 kg water if 400 kJ of energy is transferred is 47.62 °C
q = m c ΔT
q = Heat
m = Mass
c = Specific heat
ΔT = Change in temperature
q = 400 KJ
m = 2 kg
c = 4200 J/kg °C
ΔT = q / m c
ΔT = 400 * 10³ / 2 * 4200
ΔT = 47.62 °C
The quantity of heat energy required to change the temperature of particle by 1 °C is known as heat capacity. Specific heat capacity is the heat capacity is calculated for 1 gram of matter.
Therefore, the temperature increase of water is 47.62 °C
To know more about change in temperature
https://brainly.com/question/23411503
#SPJ1
A flowerpot falls from a window sill 34.6 m
above the sidewalk.
What is the velocity of the flowerpot when
it strikes the ground? Choose upwards to be
the positive y direction. The acceleration of
gravity is 9.81 m/s²
The velocityof the flowerpot when it strikes the ground is 26.04.
What is velocity.
velocity is the prime indicator of the position as well as the rapidity of an object. It can be defined as distances covered by an object in unit of the time. velocity can defined as the displacement of the object in unit of the time .
Sol- As we know when the object is simply falls it's initial velocity is 0.
Therefore u=0
Given question is flowerpot traveled 34.6 before striking the ground.
Therefore s=34.6
We have to find v?
v^2= u^2+2gs
v^2= 0+2gs
v=√2gs
v=√2×9.81×34.6
v=26.04
To know more about velocity click-
https://brainly.com/question/25749514
#SPJ9
free fall is any motion of a body where is the only force acting upon it
If the lines in problem below, have a resistance of 100-Ω, calculate the change of voltage along each line. We are asked to determine the current given the power and the voltage. To do that we will use the following formula:P=IVWhere:P= powerI= currentV= voltageNow, we divide both sides by "V":PV=INow, we convert the power from "kW" to "W" using the following conversion factor:1kW=1000WMultiplying by the conversion factor we get:200kW×1000W1kW=200000WNow, we plug in the values in the formula:200000W48000V=ISolving the operations:4.2A=ITherefore, the current is 4.2 Amp.
Resistance 100
Current 4.2A
Based on the information of the last point, we know the current and now we have the resistance. With these two numbers we can calculate the drop of voltage generated by the resistance.
Is important to highlight that we asume the same current for each line because the current is constant in all the parallel lines.
[tex]\begin{gathered} V=IR \\ V=100\Omega\cdot4.2A \\ V=420V \end{gathered}[/tex]A tetherball leans against the smooth, frictionless
post to which it is attached (Figure 1). The string is
attached to the surface of the ball such that a line
along the string passes through the center of the
ball. The string is 1.40 m long, and the ball has a
radius of 0.110 m with mass 0.280 kg.
After thoroughly calculating we have come to find that, the tension in the string is 2.752 N
What is tension?In physics, tension is defined as the pulling force transmitted axially by a string, cable, chain, or other similar object, or by each end of a rod, truss member, or other similar three-dimensional object.
Tension can also be defined as the action-reaction pair of forces acting at each end of the aforementioned elements. Compression's opposite, tension, is possible.
We know that
Tension = (Mass × gravity) / cos∅
Here given that
Mass = 0.280kg
Gravity = 9.8 m/s²
∅ = 4.2°
Lets substitute the values and we get
Tension = (280g × 9.8 m/s²) / cos4.2°
Tension = 2.752 N
Learn more about tension
https://brainly.com/question/26714464
#SPJ9
Full question
A tetherball leans against the smooth, frictionless
post to which it is attached (Figure 1). The string is
attached to the surface of the ball such that a line
along the string passes through the center of the
ball. The string is 1.40 m long, and the ball has a
radius of 0.110 m with mass 0.280 kg. What is the
tension in the string?
A car of mass 1101 kg traveling at 18.39 m/s collides and sticks to a car with a mass of 1050 kg initially at rest. What is the resulting velocity of the two cars right after the collision, assuming that there's no friction present?
Answer: the resulting velocity of the two cars right after the collision is 9.41 m/s
Explanation:
The formula for calculating momentum is expressed as
momentum = mass x velocity
According to the law of conservation of momentum, initial momentum = final momentum
The formula for initial momentum is
m1u1 + m2u2
where
m1 = mass of first car
u1 = initial velocity of first car
m2 = mass of second car
u2 = initial velocity of second car
From the information given,
m1 = 1101
u1 = 18.39
m2 = 1050
u2 = 0 because it is at rest
Initial momentum = 1101 x 18.39 + 1050 x 0 = 20247.39
Since the cars stick together after collision, they would have a common velocity, V. Thus,
final momentum = (m1 + m2)V
final momentum = (1101 + 1050)V = 2151 V
Thus,
20247.39 = 2151 V
V = 20247.39/2151
V = 9.41
the resulting velocity of the two cars right after the collision is 9.41 m/s
A stone is thrown upword from the top of a 59.4m high cliff with an upword velocity component of 19.6m/s how long is stone in the air?
The time taken up to which the stone will be in the air is 4.01 seconds.
Here we are dealing with free falling which is referred to as A free falling object is an object that's falling beneath the sole impact of gravity. Any object that's being acted upon as it were by the force of gravity is said to be in a state of free fall. As we are given the velocity which is 19.6 m/s and the height which is 59.4 m.
So the in the first case when the stone travels for a certain distance until its velocity becomes zero.
The formula we are referring to for calculating the maximum height which is v² = u² - 2gh , where v is the final velocity , u is the intial velocity ,g is the acceleration due to gravity and h is the height.
So at v=0
=> h= u²/2g
=> h = (19.6)2/( 2*9.8)= 19.6 m
Whereas when the stone starts to freely fall, so
h = 1/2*gt², here the time taken will be, t = √(2h/g)
where h = sum of the height of the building and the height traveled after the throw
which is 19.6 m+59.4 =79
So , t = √(2h/g)
=>t = √2*(79) /9.8 = 4.01 second
To know more about free fall refer to the link https://brainly.com/question/13299152?referrer=searchResults.
#SPJ1
Which of the following scenarios where a ball is in motion describes balanced forces? (choose only one answer choice) Select one or more: a. 2, 4, and 5 b. 1, 3, and 4 c. 2 and 4 d. 1, 2, and 5
The scenario where a ball in motion describes balanced forces is 1, 3, and 4. That is option B.
What is motion?Motion is defined as the movement of an object from one position to another with respect to time.
There are different type of motion which include the following:
linear motion,rotary motion,reciprocating motion, oscillating motion.Periodic motion, andCircular motion.When an object is in motion, the forces acting on them are said to be balanced when they are equal in magnitude and in opposite directions.
1N + 3N = 4N
This shows that the forces 1N + 3N which is equal to 4N are equal and opposite.
Learn more about force here:
https://brainly.com/question/25748369
#SPJ1
Pls answer. Will rate 5 start and give a Thanks or Brainliest.
What are the characteristics of the Sun? (Select all that apply.)
Group of answer choices
The Sun is the center of our solar system and radiates energy.
The Sun is a medium-sized star compared to other stars in the universe.
The Sun has planets and dwarf planets that orbit it.
The Sun is composed of helium and hydrogen.
The Sun is near the end of its life.
The Sun is composed of helium and hydrogen. Option C.
The photosphere chromosphere and corona are all part of the Sun's atmosphere. Although the corona is sometimes called the solar atmosphere it is actually the sun's upper atmosphere. The sun's atmosphere includes features such as sunspots, coronal holes, and solar flares the sun is a star.
It's a huge spinning ball of hot gas. The sun is like a star in the night sky. Because we are so close it appears much larger and brighter than other stars. The sun is the center of the solar system and accounts for most of the mass of the solar system. Compared to the billions of other stars in the universe, the sun stands out. But for the Earth and the other planets orbiting around it, the Sun is a powerful focal point.
Learn more about The characteristics here:-https://brainly.com/question/12265031
#SPJ1
You can buy 50 rolls of toilet paper for $12.50. Write a ratio showing the unit rate of rolls per $1.
Answer:
[tex]\frac{4R}{1D}\Rightarrow\text{ 4 rolls per \$1}[/tex]Explanation: We need to find the unit rate or rate of rolls per $1:
[tex]50\text{rolls }\Rightarrow\text{ 4=\$12.50}[/tex]To find the number of rolls per one dollar we simply need to take the ratio of the two as follows:
[tex]\frac{50R}{12.50D}\Rightarrow(1)[/tex]Simplifying (1) gives the answer as follows:
[tex]\begin{gathered} \frac{50R}{12.50D}=\frac{4R}{1D} \\ \end{gathered}[/tex]The answer therefore is:
[tex]\text{4 rolls per \$1}[/tex]