Answer:
20 ft
Explanation:
This is the length where the direct contact could be used as ground electrode
PE = 0.5 × k × x²
PE potential Energy
k spring constant
x stretch/compression of the spring
Answer:
C. 30.6m
Explanation:
To find the height of the tower, we are to use Newtons law of motion to solve this problem. Since the penny is falling from the top of the tower, it is acted by the acceleration due to gravity. The formula to be used is:

Where H is the height of the tower, t is the time taken to hit the ground, u is the initial velocity and g is the acceleration due to gravity.
Given that, t = 2.5 s, g =9.8 m/s², u = 0 m/s (at the top of tower)

The IMA of the pulley shown is 2.