Answer:
75 N
Explanation:
In this problem, the position of the crate at time t is given by

The velocity of the crate vs time is given by the derivative of the position, so it is:

Similarly, the acceleration of the crate vs time is given by the derivative of the velocity, so it is:
[m/s^2]
According to Newton's second law of motion, the force acting on the crate is equal to the product between mass and acceleration, so:

where
m = 5.00 kg is the mass of the crate
At t = 4.10 s, the acceleration of the crate is

And therefore, the force on the crate is:
