Answer:
The mouse runs faster to have the same kinetic energy as the elephant.
Explanation:
Note from the equation given, mass (m) is directly proportional to KE. This means an elephant with more mass will have more KE, therefore, for the mouse to compensate, it has to run faster because its KE is smaller because of its small mass. If both run at the same speed, the elephant would have thousands of times more kinetic energy than the mouse. So the mouse has to run faster so that its speed compansates for its smaller weight.
Answer:
1.37 rad/s
Explanation:
Given:
Total length of the tape is,
m
Total time of run is,
hours
We know, 1 hour = 3600 s
So, 2.1 hours = 2.1 × 3600 = 7560 s
So, total time of run is,
s
Inner radius is, 
Outer radius is, 
Now, linear speed of the tape is, 
Let the same angular speed be
.
Now, average radius of the reel is given as the sum of the two radii divided by 2.
So, average radius is, 
Now, common angular speed is given as the ratio of linear speed and average radius of the tape. So,

Therefore, the common angular speed of the reels is 1.37 rad/s.
The greater the mass the greater is inertia.
C it reduces the amount of useful work done on objects move it up the ramp