Solve Kinematics Problem: Dropping 15.0 m, Stretching Net 1.0 m

[H^w]

Homework Statement

A person jumps from a window into a fire safety net. The person drops 15.0 meters, stretching the net 1.0 meter. What is the average deceleration before coming to rest?

Homework Equations

All of the constant acceleration equations should apply here.

The Attempt at a Solution

Well it would be sad to call this an attempt. But here goes.

I collected everything I knew about the motion.

The person is in free fall, therefore I know that Vminimum is at t=0

V 1=0 m/s a=9.8 m/s and the total displacement I believe should be 16.0 meters because the net stretched 1.0 meter whether or not that's relevant I'm not sure.

So where to go from here is my real problem.

Thanks

 

[Kurdt]

Assume the person starts from rest. You will have to find the speed the person is traveling just before they hit the net. Then you will need to find the time taken to travel one meter when they hit the net. Then you can work out the average acceleration.

$$a=\frac{\Delta v}{\Delta t}$$

 

[H^w]

What I am not understanding is I only have a, and initial velocity (V=0).

So how do I solve for t and V final?

 

[Kurdt]

Assume the jumper has an initial velocity of 0m/s. One can use the following kinematic equation to find their velocity 15 meters below the jumping point.

$$v^2 = u^2 + 2as$$

Now you know that at the 15 meter point the person hits the net and comes to a velocity of 0 m/s in 1 meter. You can employ another kinematic equation involving the initial and final velocity and the distance to find the time taken. Then you will have enough information to work out the average acceleration.