Answer:
5730 yr
Explanation:
25 = 100 (1/2)^11460/x where x = half life
.25 = (1/2)^11460/x
log .25 / log.5 = 11460/x
x = 5730 yr
A nearsighted eye has a far point of 100 cm. Objects further than 100 cm are not seen clearly. A diverging lens is used to permit clear vision of an object placed at infinity. Find the focal length of the lens.
A diverging lens is used to permit clear vision of an object placed at infinity. The focal length of the lens is -100 cm.
What is focal length?The focal length is half of the radius of curvature of the focal lens.
By the lens maker formula,
1/f = 1/v +1/u
where, v is the image distance and u is the object distance.
Give, the object is at infinity and the image must form at 100 cm, the the focal length will be
1/f = 1/ -100 + 1/∞
f = -100 cm
The focal length must be -100 cm for the diverging lens.
Learn more about focal length.
https://brainly.com/question/16188698
#SPJ1
3. Assume that a sample decays with a given half-life. Will you be able to observe when the sample has completely decayed? Why or why not?
Answer:
No
Explanation:
It will never decay to zero
after one half life there is 1/2 left
after the next half life thee is 1/2 * 1/2 = 1/4 left
then 1/8th then 1/16 th then 1/32 1/64 1/128 ........to infinity
while htere is a VERY small amount left , there will never be ZERO left
Which is not a formal planet?
A: neptune
B: uranus
C: saturn
D: jupiter
E: pluto
Answer:
Pluto
Explanation:
Pluto is now classified as a dwarf planet It used to be a formal planet but not anymore.
Is quartzite a mineral, a rock, or neither?
An automobile moves on a level horizontal road in a circle of radius 40.0 m. The coefficient of friction between tires and road is 0.60. The maximum speed with which this car can round this curve is
Answer:
Approximately [tex]15\; {\rm m\cdot s^{-1}}[/tex] (assuming that [tex]g = 9.81\; {\rm m\cdot s^{-2}}[/tex].)
Explanation:
Let [tex]m[/tex] denote the mass of this vehicle, and let [tex]g[/tex] denote the gravitational field strength.
Since the road is level, the normal force that the road exerts on the vehicle would be equal in magnitude to the weight [tex]m\, g[/tex] of this vehicle. That is: [tex]F_\text{normal} = m\, g[/tex].
Let [tex]\mu_{k}[/tex] denote the coefficient of (kinetic) friction between the tires of this vehicle and the road. The maximum friction that the road could exert on this vehicle would be:
[tex]\begin{aligned}& F_\text{max. friction} && (\text{max. friction}) \\ =\; &\mu_{k}\, F_\text{normal} && (\text{coefficient of friction}) \,(\text{normal force}) \\ =\; & \mu_{k}\, m\, g\, \end{aligned}[/tex].
Also because this road is level, the only unbalanced force on this vehicle would be friction. Thus, the net force on this vehicle would be equal to the friction that the road exerts on the vehicle, which is at most [tex]\mu_{k}\, m\, g[/tex]:
[tex]\begin{aligned}& F_\text{net} && (\text{net force}) \\ =\; & F_\text{friction} && (\text{friction}) \\ \le \; & F_\text{max. friction} && (\text{max. friction})&\\ =\; & \mu_{k}\, m\, g\, \end{aligned}[/tex].
In other words, [tex]F_\text{net} < \mu_{k}\, m\, g[/tex]. This inequality could provide an upper bound on the acceleration of this vehicle:
[tex]\begin{aligned}& a && (\text{acceleration}) \\ =\; & \frac{F_\text{net}}{m} && \genfrac{}{}{0em}{}{(\text{net force})}{(\text{mass})}\\ \le \; & \frac{\mu_{k}\, m\, g}{m} \\ =\; & \mu_{k}\, g\end{aligned}[/tex].
Thus, the maximum acceleration of this vehicle on this road would be [tex]a_\text{max} = \mu_{k}\, g[/tex].
Let [tex]r[/tex] denote the radius of this circle. When the vehicle is moving around this circle at a speed of [tex]v[/tex], the (centripetal) acceleration of this vehicle would continuously be [tex]a = (v^{2} / r)[/tex].
Since the upper bound of the acceleration of this vehicle is [tex]a_\text{max} = \mu_{k}\, g[/tex], rearrange the equation [tex]a = (v^{2} / r)[/tex] to find an upper bound on speed [tex]v[/tex]:
[tex]\begin{aligned}\frac{v^{2}}{r} &= a \\ & \le a_{\text{max}} \\ &= \mu_{k}\, g\end{aligned}[/tex].
[tex]v^{2} \le \mu_{k}\, g\, r[/tex].
[tex]v \le \sqrt{\mu_{k}\, g\, r}[/tex].
In other words, when the radius of the circle is [tex]r[/tex], the coefficient of friction between the tire and the ground is [tex]\mu_{k}[/tex], and the gravitational field strength is [tex]g[/tex], the maximum speed of the vehicle would be [tex]\sqrt{\mu_{k}\, g \, r}[/tex].
In this question, it is given that [tex]r = 40.0\; {\rm m}[/tex] whereas [tex]\mu_{k} = 0.60[/tex]. Assuming that [tex]g = 9.81\; {\rm m\cdot s^{-2}}[/tex], the maximum speed of this vehicle would be:
[tex]\begin{aligned}v_\text{max} &= \sqrt{\mu_{k}\, g\, r} \\ &= \sqrt{0.60 \times 9.81\; {\rm m\cdot s^{-2}} \times 40.0\; {\rm m}} \\ &\approx 15\; {\rm m\cdot s^{-1}}\end{aligned}[/tex].
You are driving on a highway and your gas pedal gets jammed. You cannot reduce engine power. You should keep your eyes on the road and
You should keep your eyes on the road and shift into neutral when gas pedal gets jammed.
What is Neutral?In automobiles, shifting into neutral won't transmit power to the wheels and the direction of the steering wheel can still be controlled.
This helps to prevent accidents on the road as a result of such malfunctions in the car.
Read more about Automobiles here https://brainly.com/question/25749312
#SPJ4
Research indicates that high serotonin levels may increase aggression. please select the best answer from the choices provided t f
The statement 'research indicates that high serotonin levels may increase aggression' is FALSE.
What is serotonin?Serotonin is a chemical messenger (i.e., a hormone) used to transmit messages through the body.
Serotonin is generated by the nerve cells (neurons) of the central nervous system (CNS).In conclusion, the statement 'research indicates that high serotonin levels may increase aggression' is FALSE.
Learn more on serotonin here:
https://brainly.com/question/5394922
#SPJ4
A 9-volt battery is connected to a 4-ohm resistor and a 5-ohm resistor as shown in the diagram above. How much current flows through the 4-ohm resistor?
1.0 A
1.8 B
2.3 C
4.0 D
The current flowing in the 4 ohms resistor connected in series with 5-ohm resistor is determined as 1.0 A.
Equivalent resistance of the circuit
The equivalent resistance of the circuit is determine as follows;
Rt = R1 + R2
Rt = 4 ohms + 5 ohms = 9 ohms
Current flowing in the 4 ohms resistorThe current flowing in the 4 ohms resistor is determined from Ohms law as shown below;
V = IR
I = V/R
I = 9/9
I = 1.0 A
Since the circuit is in series arrangement, same current will flow in 5 ohm and 4 -ohm.
Learn more about current here: https://brainly.com/question/24858512
#SPJ1
What are the characteristics of the bowling ball that give it lots of momentum?
a. it's big
b. it's heavy
c. it's moving quickly
Answer:
b i think
Explanation:
Water’s property of surface tension is due to _____.
A. capillary action
B. solubility
C. cohesion
D. adhesion
E. All of the above
Explanation:
It is due to cohesion (option C)
If you touch a conductor through which electricity flows with an insulator, will you receive a shock? Explain.
If you touch a conductor through which electricity flows with an insulator, the likelihood of receiving a shock depends on several factors, including the voltage and current of the electrical source, the amount of insulation present, and how well the insulation is able to insulate from the electricity.
Insulators are materials that do not conduct electricity and are commonly used to provide a barrier between humans and electrical conductors to prevent electrical accidents. When an insulator is used to touch a conductor through which electricity flows, the insulator acts as a barrier and prevents the current from flowing through the material and into the body.
However, if the insulation is inadequate or damaged, or the voltage of the electrical source is high enough to overcome the insulating properties of the material, a shock can occur. The shock occurs when the current passes through the body, causing damage to organs, muscles, and nerves.
Therefore, it is important to ensure that proper insulation practices are followed when working with electrical conductors, and to use insulation materials that are sufficient to protect against the voltage and current levels of the electrical source being used. Generally, it is recommended to avoid touching electrical conductors altogether, as the risk of electrical accidents is always present.
For such more questions on electricity
https://brainly.com/question/27600426
#SPJ11
No, you will not receive a shock if you touch a conductor through which electricity flows with an insulator. An insulator is a material that does not conduct electricity, meaning it does not allow the flow of electric current.
It has high resistance and acts as a barrier, preventing the transfer of electrons. Therefore, when you touch a conductor with an insulator, the insulator acts as a protective layer that blocks the flow of electric current and prevents it from reaching your body. As a result, you will not experience a shock. However, it is important to note that the effectiveness of the insulator in preventing a shock depends on its quality and condition. If the insulator is damaged or has a low resistance, it may not provide adequate protection, and there is a risk of electric shock. Additionally, it is crucial to follow safety protocols and avoid touching conductors or working with electricity unless you are trained and have the necessary knowledge and equipment to do so safely.
for more such questions on electricity
https://brainly.com/question/776932
#SPJ11
A student shakes a rope such that 36 complete vibrations are
made in 9.00 seconds. determine the vibrational period of
the rope, along with the corresponding unit.
The vibrational period of the rope, when a student shakes it is 0.25 s.
What is the frequency?Frequency is the number of oscillations per second.
Given is the number of vibrations =36 in time t = 9s, then frequency will be
f = 36/9 =4Hz
The time period is the reciprocal of the frequency.
T = 1/f
Plug the frequency value, we get
T = 1/4 Hz = 0.25 seconds
Thus, the vibrational time period is 0.25s.
Learn more about frequency.
https://brainly.com/question/25867078
#SPJ1
Romeo and Juliet are sitting on a balcony 1.2 meters apart. If Romeo has
a mass of 69.3 kg and Juliet has a mass of 52.0 kg, what is the attractive
force between them?
F = G M.m/r²
F = force, N
G = gravitational constant, 6.67 x 10⁻¹¹ Nm²/kg²
m,M = mass of object, kg
r = distance, m
F = 6.67 x 10⁻¹¹ x 69.3 x 52/1.2²
F = 1.669 x 10⁻⁷
What is the difference between saturated and unsaturated fat? Why are partially hydrogenated fats useful for making potato chips but not particularly healthy for humans to eat?
Saturated fats have the maximum number of hydrogens possible, while unsaturated fats consists of a double bond between two of the carbon atom.
The partially hydrogenated fats useful for making potato chips but not particularly healthy for humans to eat because of presence of trans fat.
What is partially hydrogenated fats?Partially hydrogenated fats have trans fat that can raises cholesterol level in heart and result in severe health complications like heart attack.
Each carbon have four bonds to react with. In saturated fats, each carbon has four hydrogens bonded and a straight structure is formed They are solid at room temperature. So, they are remain solid in arteries of heart and block it.
Unsaturated fats have a carbon, double bonded with another carbon and gives the molecule a bent structure. They remain liquid at room temperature and are healthier fats.
The potato chips are not healthy for humans to eat. The partially hydrogenated fats raise bad cholesterol and lowers good cholesterol. The trans fats increases the risk of heart disease and can lead to death of adults. The more trans fats eaten, the greater is the risk of heart attack.
Thus, partially hydrogenated fats useful for making potato chips but not particularly healthy for humans to eat because of presence of trans fat.
Learn more about partially hydrogenated fats.
https://brainly.com/question/14318480
#SPJ1
If you have a voltage of 120 volts entering your house and a light bulb with 0.75 amperes flowing through it, how many watts is your light bulb?
30 watts
120 watts
60 watts
90 watts
Answer:
90 watts
Explanation:
Formula for Power (using voltage and current) :
P = VIP = 120 V × 0.75 AP = 90 wattsAnswer:
90 watts
Explanation:
Watts = volts x amperes
120X.75 = 90
When two forces act in the same direction on an object, the net force is found by ....................the forces.
Answer:
Net force is found by sum of the forces.
Answer:
The correct answer is When two forces act in the same direction on an object, the net force is found by the sum of the forces.
Hope this helps you!!
Please mark me Brainleast!!
Thankyou for joining Brainly communicty!!!how much work is done on a small car if a 3000 N force is exerted to move it 75 m to the side of the road ?
Answer:
Soln,
force=3000 N
distance=75 m
we know that,
work done= force × distance
= 3000× 75
= 225000 joule
How long does it take to travel?
120 miles at 40mph
Answer:
it takes 3 hours to travel
Explanation:
120 ÷ 40 = 3
Step 1. distance = speed * time or time = distance/speed.
Step 2. time = 120 miles/(40 miles/hour) = 3 hours.
Step 3. ANSWER: It would take 3 hours to travel 120 miles at 40 mph.
Describe the sound produced by an instrument of length L, that is open at both ends. Be sure to include the terms pitch, frequency, timbre, nodes and antinodes
The sound produced by an instrument of length L that is open at one end posses has a high frequency.
What is Sound?Sound is kind of vibration which travels in the form of sinusoidal wave through a medium which can be solid, liquid or gas/air.
Sound produced by an instrument which has an open end has a high
frequency and pitch, nodes , timbre and a low antinode. These are all the characteristics of a sound produced by the instrument.
Learn more about Sound.
https://brainly.com/question/1515875
#SPJ1
What are created when atoms join
together?
A. new elements
B. unstable conditions
C. molecules
Answer:
molecules
Explanation:
Molecules will be formed if atoms join together.
Three 20.0 ohm resistors are
connected in parallel and attached to
a 5.00 V battery. How much current
flows out of the battery?
Answer:
0. 75A
Explanation:
R1=20omh
R2=20omh
R3=20omh
equivalent voltage (V)= 5.00V
equivalent resistance (R) = ?
equivalent current (I)= ?
since, they are in parallel so,
1/R = 1/R1 + 1/R2 + 1/R3
1/R = 1/20 + 1/20 + 1/20
1/R = 3/20
R = 6.67 ohm
Now,
from ohm's law
V= IR
or, 5 = 6.67*I
or, I = 0.749
hence, I= 0.75A
A motor lets a 450.N crate drop at a constant 5.75m/s. What is the power output of the motor?
A motor lets a 450.N crate drop at a constant 5.75m/s. What is the power output of the motor?
78.3W
2590W
444W
456W
Power is the energy per unit time required to run a machine. The output power of the motor is 2590 W.
What is power?Power is the product of force and velocity with which an object is moving.
P = F x v
Given is the force 450N and the velocity is 5.675 m/s, then the power is
P = 450 x 5.75
P = 2587.5 Watt
The power output of the motor is approximately 2590 W.
Learn more about power.
https://brainly.com/question/19168410
#SPJ1
A bicyclist heads east at 20 km/h. After she has traveled 20.8 kilometers, another cyclist sets out in the same direction going 28 km/h. About how long will it take the second cyclist to catch up to the first cyclist
Hence,the time it takes the second cyclist to catch up to the first cyclist will be 2.6 h.
What is velocity?The change of displacement with respect to time is defined as the velocity. Velocity is a vector quantity. it is a time-based component.
[tex]\rm D_{rel}= V_{rel}\times t_{rel} \\\\ \rm D_{rel}= (V_1-V_2)\times t_{rel} \\\\ T_{rel}=\frac{D_{rel}}{V_1-V_2} \\\\ T_{rel}=\frac{20.8}{28-20} \\\\ T_{rel}= 2.6 \ h[/tex]
The time it takes the second cyclist to catch up to the first cyclist will be 2.6 h.
To learn more about the velocity refer to the link ;
https://brainly.com/question/862972
#SPJ1
What spectrum can humans see? What does it break into? What is the order of color?
Answer:
the rainbow spectrum. red orange yellow green blue violet. It breaks into ultra violet.
Explanation:
Unit Test Review
Active
1
2
3
Which statement best describes heat and thermal energy?
O They are different words for the same thing.
O They represent different concepts.
O Heat is what happens when thermal energy stops moving between substances.
O Thermal energy is what happens when heat moves between substances.
Answer:
option B...
they represent different concept...
i hope this will answer your question
Which two elements undergo fusion in the sun?
Answer:
In the core of the Sun hydrogen is being converted into helium. This is called nuclear fusion. It takes four hydrogen atoms to fuse into each helium atom. During the process some of the mass is converted into energy.
What is the acceleration of a train that takes 22 seconds to go from a speed of 73 kilometers per hour to a speed of 45 kilometers per hour?
The acceleration of a train that takes 22 seconds to go from a speed of 73 kilometers per hour to a speed of 45 kilometers per hour is 0.354 m/s².
What is acceleration?
Acceleration: the rate at which the speed and direction of a moving object vary over time. A point or object going straight ahead is accelerated when it accelerates or decelerates.
Even if the speed is constant, motion on a circle accelerates because the direction is always shifting.
Acceleration is a change in velocity divided by a change in time. Given the time of 22 seconds and the distance is 73 kilometers. The speed is 45 k/h
(73 - 45 ) = 28 km / hr
Change in velocity = 7.778 m/s
7.778 m/s / 22 s = 0.354 m/s².
Therefore, the acceleration of a train is 0.354 m/s².
To learn more about acceleration, refer to the link:
https://brainly.com/question/12550364
#SPJ2
Answer:
Below
Explanation:
73 km / hr = 20.277 m/s and 45 km/hr = 12.50 m/s
Acceleration = change in velocity / change in time
(12.5 - 20.277) m/s / 22 s = - . 354 m/s^2
( NOTE the negative sign....this is a DEceleration)
is a superheated cloud of gas and dust swirling around a massive object (usually a black hole or neutron star) this cloud can reach incredible speeds and temperatures as gravity causes it to build up more and more friction, eventually releasing x rays.
a. Nebula
c. Accretion Disk
b. Proto-star
d. White Dwarf
A superheated cloud of gas and dust swirling around a massive object (usually a black hole or neutron star) is called an accretion disk. The correct option is c.
What is accretion disk?Accretion disk is a heavy object surrounded by flow of gas, plasma, dust, or particles. The materials surrounding the heavy object orbiting in the gravitational field of the object that loses energy and angular momentum as it slowly spirals inward.
This cloud can reach incredible speeds and temperatures as gravity causes it to build up more and more friction, eventually releasing x rays.
Thus, accretion disk is a superheated cloud of gas and dust swirling around a massive object.
Learn more about accretion disk.
https://brainly.com/question/1900229
#SPJ1
When two objects made of different materials are rubbed together, they will attract each other after the charging process.Immersive Reader (1 Point) True False
Answer:
True
Explanation:
because their is friction(e.g take a ruler rub it in your hair then put it on top of a piece of paper on the table then u will see the process)among the two objects.
PLEASE HELP
Which of the following is a characteristic property of the alkaline earth
metals?
A. They are harder than alkali metals.
B. They are more reactive than alkali metals.
C. They all have 3 valence electrons.
D. They are all radioactive.
Answer:
It's D, they're all radioactive. This is due to the molecules that it is made up of
Answer:
the answer is A
Explanation:
I hope it helps you