Answer:
86.4 m horizontal from landing spot
Explanation:
Find out how long before the ball hits the ground
vertical speed of ball = -2 m/s gravity = - 9.81 m/s^2
find time to hit ground from 100 m
( height will be<u> zero</u> when it hits the ground)
<u>0 </u>= 100 - 2 t - 1/2 ( 9.81) t^2
use Quadratic Formula to find t = 4.32 seconds
horizontal speed of ball = 20 m/s
in 4.32 seconds it will travel horizontally 20 m/s * 4.32 s = 86.4 m
it would be..... C
sorry if I am wrong I tryed to think, At least I try!
The elastic potential energy of a spring is given by

where k is the spring's constant and x is the displacement with respect to the relaxed position of the spring.
The work done by the spring is the negative of the potential energy difference between the final and initial condition of the spring:

In our problem, initially the spring is uncompressed, so

. Therefore, the work done by the spring when it is compressed until

is

And this value is actually negative, because the box is responsible for the spring's compression, so the work is done by the box.