Explanation:
Given: Initial Velocity=0
Final Velocity= 20 m/s
Time= 4 s
Accleration: Unknowns
Use kinematic equation




so a = 5 m/s^2
Forget about the car's speed. You don't need it.
The tires spin 840 rpm. That's 840 <em>Revolutions per Minute</em> .
There are 60 seconds in 1 minute. So something that happens 840 times in 1 minute happens (840 / 60) times every second.
(840 rev per minute) / (60) = <em>14 revs per second</em> .
I believe the answer is D. Thermal Conductivity
Answer:
c. an increase in the length of the rope.