We are given the following values:
weight w = 240 lb = 1,067.52 N
energy E = 3,000 J
The formula for potential energy is:
E = w h
where h is the height the person has to climb, therefore:
h = 3000 / 1067.52
<span>h = 2.81 m</span>
<span>
</span>
<span>Therefore he has to climb 2.81 meters</span>
Answer:
0.83 m or 5.57 m
Explanation:
Destructive interference will occur when the distances from the speakers differ by 1/2 wavelength.
The length of 1 cycle of 72.4 Hz is ...
λ = v/f = (343 m/s)/(72.4 Hz) ≈ 4.738 m
So, the distance of the listener from speaker B is ...
3.2 m ± (4.738 m)/2 = {0.83 m, 5.57 m} . . . either of these distances
_____
The location could be at additional multiples of 4.738 m, but we think not. The sound intensity drops off with the square of the distance from the speaker, so identical sound waves from the speakers will sound quite different at different distances from the speakers. For best interference, the distances need to be as close to the same as possible. That will be at 3.2 m and 5.57 m.
_____
<em>Comment on the speed of sound</em>
We don't know what speed you are to use for the speed of sound. We have used 343 m/s. Some sources use 340 m/s, which will give a result different by 2 or 3 cm.
Answer:
.c. −160°C
Explanation:
In the whole process one kg of water at 0°C loses heat to form one kg of ice and heat lost by them is taken up by ice at −160°C . Now see whether heat lost is equal to heat gained or not.
heat lost by 1 kg of water at 0°C
= mass x latent heat
= 1 x 80000 cals
= 80000 cals
heat gained by ice at −160°C to form ice at 0°C
= mass x specific heat of ice x rise in temperature
= 1 x .5 x 1000 x 160
= 80000 cals
so , heat lost = heat gained.
Answer:
As the person moves down the zip wire, her increase in kinetic energy is less than her decrease in gravitational potential energy.
Explanation:
Work is done against the air resistance, causing thermal energy to transfer to the surroundings
Answer: X
Explanation:
This situation can be illustrated as a car in circular motion (image attached).
In circular motion the acceleration vector 
is always directed toward the center of the circumference (that's why it's called centripetal acceleration).
So, in this case the arrow labeled X is the only that points toward the center, hence it represents the car's centripetal acceleration
