A child of mass 40kg jumps off a wall and hits the ground at 4m/s.He bends his knees and stops in 1s.Calculate the force required to slow him down.How would this force be d/t if he didn't bend his knees and stopped in 0.1s?

160N

KE = Ft

Solve for F

This physics

answer

16N

To calculate the force required to slow down the child, we can use Newton's second law of motion, which states that force is equal to mass multiplied by acceleration. In this case, the force required to slow down the child is equal to the product of the child's mass and the deceleration he experiences.

First, we need to calculate the deceleration. Deceleration is given by the change in velocity divided by the time taken for the change to occur. In this case, the velocity changes from 4 m/s to 0 m/s, taking 1 second.

Deceleration = (final velocity - initial velocity) / time taken
Deceleration = (0 m/s - 4 m/s) / 1 s
Deceleration = -4 m/s^2

Since the velocity is decreasing, the deceleration is negative.

Now, we can calculate the force using Newton's second law:

Force = mass x acceleration
Force = 40 kg x (-4 m/s^2)
Force = -160 N

Therefore, the force required to slow down the child is 160 N. The negative sign indicates that the force is in the opposite direction of the child's motion.

Now, let's consider the scenario where the child doesn't bend his knees and stops in 0.1 seconds. In this case, the time taken for the change in velocity is 0.1 seconds.

Using the same formula as before:

Deceleration = (final velocity - initial velocity) / time taken
Deceleration = (0 m/s - 4 m/s) / 0.1 s
Deceleration = -40 m/s^2

Again, we have a negative deceleration since the velocity is decreasing.

Now, let's calculate the force:

Force = mass x acceleration
Force = 40 kg x (-40 m/s^2)
Force = -1600 N

Therefore, the force required to slow down the child in the second scenario is 1600 N.

To summarize:

- If the child bends his knees and stops in 1 second, the force required is 160 N.
- If the child doesn't bend his knees and stops in 0.1 seconds, the force required is 1600 N.

The force required is greater when the child doesn't bend his knees and the stopping time is shorter.