Answer:
The well is 7.1 meters deep.
Explanation:
The formula to use here is the distance in a uniformly accelerated motion:

where d stands for distance, t for time, a for acceleration, v0 and d0 for initial velocity and distance, respectively. Since the initial distance and velocity are both zero, we are left with the first term. The coin is in free fall and so it is accelerated by gravity:

The well is 7.1 meters deep.
A ) decrease.
B ) increase.
C ) increase, then decrease.
D ) not change.
The answer is A) decrease
Take pushing a box, for example-- You push your hardest then give out, still trying to push the box. You are doing less work than what you have started with!
( Mind marking me for branliest? ; ) )
KE = 1/2mv^2
1/2(10.5)(9)^2
1/2(10.5)(81) = 425.25 J
First, convert all the km/hr into m/s
You will get that
initial speed = 20 m/s
Initial speed of Green train = 40 m/s
Initial separation = 950 m
Velocity of approach = 20 - -40 = 60 m/s
relative acceleration = -4 m/s^2
v = u + at
0 = 60 - 4t
t = 15s
s = ut + 1/2 *at * t
s = 60 * 15 - 1/2 *4 * 225
s = 900 - 450
Separation when they stop = 450 m
hope this helps