I believe a and b are correct. I asked the is twice, but i am unable to read wha

Question

I believe a and b are correct. I asked the is twice, but i am unable to read what was written and no formulas were given for c and d. I appreciate your help thank you

8. A worker on a flatbed railroad car is pushing a crate. The train is moving at a constant speed of 15.0 m/s. The crate has a mass of 12 Kg, and in being pushed forward over a distance of 2.4 m its velocity is increased (relative to the car) at constant acceleration from rest to 1.5 m/s. (a) What are the crate's displacement, initial velocity, final velocity, and acceleration as measured by an observer inside the train and another standing on the ground? (b) Find the force acts on the crate as measured by each observer? (c) Show that the work done on the crate is equal to the change in its kinetic energy for each observer. (d) If the crate starts to move with constant velocity of 1.5 m/s at the end of the 2.4 m and the driver of the train applies the brakes, the train begins to decelerate with constant rate of -2.8 m/s, find the force acts on the crate according to each observer?

Explanation / Answer

a. given v = 15 m/s
m = 12 kg
d = 2.4 m
uo = 0 m/s
ui = 1.5 m/s

with respect to ground
time taken = t
2*a*d = ui^2 - uo^2
a = 0.46875 m/s/s
ui = uo + a*t
t = 3.2s
crates' displacement = vt + 2.4 = 50.4687 m

initial velocity = 15 m/s
final velocity = 15 + 1.5 = 16.5 m/s
acceleration for person on train = 0.46875 m/s/s
for a person on ground, a = (16.5 - 15)/t = 0.46875 m/s/s

b. as accelration os the same
froce = m*a = 5.625 N

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