# Homework Help: Crazy problem about impulse

1. Nov 10, 2007

### dominus96

1. The problem statement, all variables and given/known data

In February 1955, a paratrooper fell 370 m from an airplane without being able to open his chute but happened to land in snow, suffering only minor injuries. Assume that his speed at impact was 60 m/s (terminal speed), that his mass (including gear) was 80 kg, and that the force on him from the snow was at the survivable limit of 1.2*10^5 N.

(a) What is the minimum depth of snow that would have stopped him safely?

(b) What is the magnitude of the impulse on him from the snow?

2. Relevant equations

delta P = F*t
F=ma?

3. The attempt at a solution

I have no clue, I've never seen a problem like this before...

2. Nov 10, 2007

### catkin

3. Nov 10, 2007

### rl.bhat

Paratrooper's mass and treminal velocity is given. Find his KE when he touches the ground. Finally he stops. Change in KE = Force X Displacement.

4. Nov 10, 2007

### aq1q

5. Nov 10, 2007

### dominus96

I found KE, but what does that have to do with impulse? I thought impulse was change in momentum?

6. Nov 10, 2007

### aq1q

impulse is mV1-mV2

7. Nov 10, 2007

### aq1q

but KE will tell u what velocity the man lands at the snow

8. Nov 10, 2007

### dominus96

mv1 - mv2...is that like P1 - P2? (P stands for momentum)

9. Nov 10, 2007

### Vidatu

Yes. Now that you have kinetic energy, you have everything you need to solve this.