You testify as an expert witness in a case involving an accident in which car A slid into the rear of car B, which was stopped at a red light along a road headed down a hill (Fig. 6-25). You find that the slope of the hill is u " 12.03, that the cars were separated by distance d " 24.0 m when the driver of car A put the car into a slide (it lacked any automatic anti-brake-lock system), and that the speed of car A at the onset of braking was v0 " 18.0 m/s.With what speed did car A hit car B if the coefficient of kinetic friction was (a) 0.60 (dry road surface) and (b) 0.10 (road surface covered with wet leaves)
Answer:
A) 12.08 m/s
B) 19.39 m/s
Explanation:
A) Down the hill, we will apply Newton’s second law of motion in the downward direction to get:
mg(sinθ) – F_k = ma
Where; F_k is frictional force due to kinetic friction given by the formula;
F_k = (μ_k) × F_n
F_n is normal force given by mgcosθ
Thus;
F_k = μ_k(mg cosθ)
We now have;
mg(sinθ) – μ_k(mg cosθ) = ma
Dividing through by m to get;
g(sinθ) – μ_k(g cosθ) = a
a = 9.8(sin 12.03) - 0.6(9.8 × cos 12.03)
a = -3.71 m/s²
We are told that distance d = 24.0 m and v_o = 18 m/s
Using newton's 3rd equation of motion, we have;
v = √(v_o² + 2ad)
v = √(18² + (2 × -3.71 × 24))
v = 12.08 m/s
B) Now, μ_k = 0.10
Thus;
a = 9.8(sin 12.03) - 0.1(9.8 × cos 12.03)
a = 1.08 m/s²
Using newton's 3rd equation of motion, we have;
v = √(v_o + 2ad)
v = √(18² + (2 × 1.08 × 24))
v = 19.39 m/s
127) A swimmer heading directly across a river that is 200 m wide reaches the opposite bank in
6 min 40 s. During this swim, she is swept downstream 480 m. What is the speed of the
current?
A) 0.50 m/s
B) 0.80 m/s
C) 1.2 m/s
D) 1.4 m/s
E) 1.8 m/s
Answer:
C
Explanation:
energy
Potential energy + Kinetic energy
OA) Heat
OB) Chemical
Electrical
OD) Mechanical
help i need step by step awnser
Answer:
Gold
Silver
Mixture
Explanation:
Density
The density of an object of mass m and volume V is given by:
[tex]\displaystyle d=\frac{m}{V}[/tex]
We are given the following densities:
Gold: 19.3 gr/cm3
Silver: 10.5 gr/cm3
With the data provided in the table, we can confirm which of the three columns corresponds to gold, silver, or a mix of both.
Calculating the first density: m1=1,930 gr, V1=100 cm3
[tex]\displaystyle d1=\frac{m1}{V1}[/tex]
[tex]\displaystyle d1=\frac{1,930}{100}[/tex]
[tex]d1=19.3\ gr/cm^3[/tex]
This crown is made of gold
Calculating the second density: m2=1,930 gr, V2=184 cm3
[tex]\displaystyle d2=\frac{m2}{V2}[/tex]
[tex]\displaystyle d2=\frac{1,930}{184}[/tex]
[tex]d2\approx 10.5\ gr/cm3[/tex]
This crown is made of silver
Calculating the last density: m3=1,930 gr, V3=150 cm3
[tex]\displaystyle d3=\frac{m3}{V3}[/tex]
[tex]\displaystyle d3=\frac{1,930}{150}[/tex]
[tex]d3\approx 12.9 gr/cm^3[/tex]
Since the value of the density is between gold and silver, this crown is a mixture.
If the force being applied to an object is doubled, what will happen to its
acceleration?
Answer:
Acceleration decreases.
Explanation:
Hope this helps you.
If you are doing 4 sets of 10 repetitions of air squats you are doing _____ x _____ which equals to _____ air squats
Answer:
4x10=30
Explanation:
You can easily know it's multiplication when you see the sign. It gives you the number but you have to plug it in. So once you plug in the numbers then you should get either 4x10 or 10x4 which means both is equal to 40
Why is science good for democracy
Answer:
Equitable education in a healthy democracy includes science and engineering learning for every student. Great science and engineering education engage student so that they develop the knowledge and intellectual dispositions to make sense of the natural and designed worlds.
Explanation:
4. Cliff divers at Acapulco jump into the sea from a cliff 36.0m high. At the level of the sea, a rock sticks out a horizontal distance of 6.00m. With what minimum horizontal velocity must the cliff divers leave the top of the cliff if they are to miss the rock?
Answer: 5.5
Explanation: its simply different from the others
can fertilizer grow plants (physics )
Answer:
A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply one or more plant nutrients essential to the growth of plants. Many sources of fertilizer exist, both natural and industrially produced.
Explanation:
During a spacewalks an astronaut lets go of a tool, causing it to float away and bounce off the side of the space shuttle. The astronaut saw
the the tool hit the shuttle but did not hear it hit the shuttle. Why would the astronaut be able to see the tool hit the shuttle but not hear it
hit the shuttle?
FISH
Answer:
In space noone can hear you scream.....
Explanation:
There is no sound in space. Sound, like light or heat, is a wave. However, one major distinction is that, unlike light or heat (radiation), sound needs a medium to travel. Sounds require the presence of molecules or particles to travel from one region to another.
does this curved graph show a function explain how you know
Answer:
No; the graph fails the vertical line test.
The vertical line test is a tool used to determine if we have a function. If we can draw a single straight vertical line through more than one point on the red curve, then the graph is said to have failed the vertical line test. Consequently, this leads to the relation not being a function.
For this circle graph, we can draw a vertical line through more than one point, which is why we don't have a function here.
Put another way, there are inputs (x) that produce more than one output (y), so that's why we don't have a function.
-BBBM
HELP WHIT PROJECT PLZZ FOR ALL MY POINTS!!!!!!!!!!! X^X
Answer:
maybe. inv me to slides and I'll try.
Explanation:
A speeding Thunderbird left skid marks on the road that were 76.7 m long when it came to a stop. If the acceleration of the car was -10 m/s2, how fast was the car initially going?
Answer: 39.2 m/s
Explanation:
You can use the kinematic equation:
[tex]v_f^2=v_i^2+2a*d[/tex]
We know the final velocity because it says it came to a stop. So now all we gotta do is plug in.
[tex]0^2=v_i^2+2(-10)(76.7)\\v_i^2=1,534\\v_i=\sqrt{1534} \\=39.166 m/s[/tex]
Students raced each other in the gym while the teacher recorded each student's speed. Jeremy ran 14 miles per hour, Isaiah ran 10 miles per hour, Jonah ran 13 miles per hour, and Alexis ran 16 miles per hour. Which of the bar graphs should the teacher use to compare the students' speeds? (pictures re the choices)
In a gym the students raced with each other and teacher is recording everyone's speed than the second graph is representing correctly.
What is a graph?A graph is a visual depiction of statistical data or a logical relationship between variables. Graphs serve a predictive purpose because they have the virtue of displaying broad trends in the mathematical behavior of data. However, as just approximations, they may be incorrect and occasionally deceptive.
Most graphs have two axes, with the axis denoting a set of independent variables and the vertical axis denoting a set of dependent variables. The most typical graph is indeed a broken-line chart, where the regression coefficient is typically a factor of duration.
In the second graph the speed of every student is represented accurately, therefore the second graph is correct.
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The anther and filament are parts of a flower's:
stamen
petal
pistil
stigma
An electric current of 0.75 A passes through a circuit that has a resistance of 175 12. According to Ohm's law, what is the voltage of the circuit? O A. 176 V O B. 0.004 V O C. 233 V O D. 131 V
Answer:
15.34 i think
Explanation:
A car traveling 6.0 m/s is uniformly accelerating at a rate of 3.0 m/s^2 for 15 seconds. What is its final velocity
Answer:
51m/s^1
Explanation:
v=u+at
v=(6)+(3)(15)
v=51m/s^1
What happens to the temperature of a substance while it is changing state?
A. It increases first and then decreases.
B. It decreases first and then remains constant.
C. It varies randomly.
D. It remains constant.
Answer:
During a phase change, the temperature will remain constant. Obviously all the heat is used in phase transformation. So the correct answer should be D. Forgive me if I'm wrong but I hope this helps!
The temperature of a substance remains constant while it is changing state. Thus, the correct option is D.
What is the relation between state and temperature of substance?Temperature has a direct effect on whether a substance exists in states as a solid, liquid, or gaseous substance. Substances can change their phase often because of a temperature change of the substance. At very low temperature conditions, most of the substances are solid, as the temperature of the substance keeps on increasing, then they become liquid and at very higher temperatures still, they become gaseous substances.
The temperature of a substance remains constant while it is changing its state.
Therefore, the correct option is D.
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What will be the velocity of a train if it covers the distance of 30m in 3 s?
Answer:
Soln:
d=30m
t=3s
now:
v=d/t
=30/3
=10
1. There is a group of kids playing tee ball in front of your house. If the bat is 5kg traveling with a velocity
of 8m/s, with what velocity will the 1.5 kg ball travel after it is hit by the bat?
Answer: tug vi
Explanation:
Because
Two ice skaters on ice push away from each other. What will be the effect of the forces of their pushing each other if their masses are different?

Answer:If the masses are different, the lighter ice skater will accelerate faster than the ice skater with more mass.
Explanation:
The lighter skater will accelerate more quickly than the heavier skater if there are mass discrepancies.
used an idea?According to Newton's third law, the action and reaction forces in any force interaction must be equal and moving in the opposite directions. These pressures, nevertheless, affect a variety of items. In this case, each skater will experience the same amount of force, and if any other horizontal forces, such as friction, operating on each skater in the opposite direction from the pushing force are less than the pushing force, each will accelerate in that direction. The two skater system's center of mass will remain where it is if there is little to no friction to prevent the skaters from moving.
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Which of the following is a correct example of the current in a light bulb?
60 Joules
60 Volts
60 Watts
60 Amperes
Answer:
60 Amperes
Explanation:
current is the main factor, so current is measured in Amperes
What happens to particle spacing when temperature increase, What we call this process?
Answer:
The atoms start vibrating really fast, making the space between them larger. It's an increase in Kinetic Energy.
A line graph usually reveals a relationship between which factors
Answer:
variables on the horizontal and vertical axis (slope, outliers, +/- correlation, etc)
Explanation:
if a runner is moving 2.88m/s directly north and accelerating at .350 m/s^2 at an angle of -52.0. At the point in the motion where she is running directly east what is the displacement
Answer:
19.1 m, 52.0°
Explanation:
Given:
v₀ₓ = 0 m/s
v₀ᵧ = 2.88 m/s
vᵧ = 0 m/s
aₓ = 0.350 m/s² cos(-52.0°) ≈ 0.215 m/s²
aᵧ = 0.350 m/s² sin(-52.0°) ≈ -0.276 m/s²
Find: Δx and Δy
First, find time.
vᵧ = aᵧt + v₀ᵧ
0 m/s = (-0.276 m/s²) t + 2.88 m/s
t = 10.4 s
Now find the displacement components Δx and Δy.
Δx = v₀ₓ t + ½ aₓ t²
Δx = (0 m/s) (10.4 s) + ½ (0.215 m/s²) (10.4 s)²
Δx = 11.7 m
Δy = v₀ᵧ t + ½ aᵧ t²
Δy = (2.88 m/s) (10.4 s) + ½ (-0.276 m/s²) (10.4 s)²
Δy = 15.0 m
The magnitude of the displacement is:
d² = Δx² + Δy²
d² = (11.7 m)² + (15.0 m)²
d = 19.1 m
The direction of the displacement is:
θ = atan(Δy / Δx)
θ = atan(15.0 m / 11.7 m)
θ = 52.0°
3. An earthquake measures 3 on Richterscale:
(i)Would it be recorded by a seismograph ?
(ii)ls it likely to cause much damage ?
Answer:
Yes, it would be recorded by a seismograph. The earthquake with magnitude of 3 on Richter Scale is not likely to cause much damageHELPPPPP
Jermaine runs exactly 2 laps around a 400 meter track.
Find displacement.
Answer:
0
Explanation:
she runs 2 whole laps around a 400 meter track, but she is always ending up back where she started, therefor there is no displacement.
what is the unit of magnetic field
Answer:
Hope this helps!~ (Sorry if you get it wrong or I got it wrong-)
Explanation:
The standard SI unit for magnetic field is the Tesla, which can be seen from the magnetic part of the Lorentz force law Fmagnetic = qvB to be composed of (Newton x second)/(Coulomb x meter). A smaller magnetic field unit is the Gauss (1 Tesla = 10,000 Gauss).
~The Confuzzeled homan
A car decelerates uniformly from 24 m/s to 18 m/s in 3.0 seconds. How far does it travel during this time?
Distance travelled will be = 63 m
What is equation of motion?
These are the equations that describe the behavior of a physical system in terms of its motion as a function of time .
Given : u = 24 m/s
v= 18 m/s
t = 3sec
using equation of motion : v = u + at
18 = 24 + a*3
-6 = 3a
a = -2 m/s^2
using equation of motion : s = u t + 1/2 a (t^2)
s = 24 * 3 + 1/2 * (-2)(9)
s = 63 m
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Which particle is used as a beam to treat cancer? electron neutron proton
Answer:neutron
Explanation:
Because it is similar to the motor neurons
Answer:
Proton
Explanation:
Proton therapy, also called proton beam therapy, is a type of radiation therapy. It uses protons rather than x-rays to treat cancer. A proton is a positively charged particle. At high energy, protons can destroy cancer cells.