# Homework Help: Arrow hitting a target average force question

1. Sep 19, 2011

### Capncanada

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

A 8.0×10−2 kg arrow hits the target at 25 m/s and penetrates 3.8 cm before stopping.

2. Relevant equations

What average force did the target exert on the arrow?

What average force did the arrow exert on the target?

3. The attempt at a solution

I found the force the arrow's exerting before it hits the target I think...
(8*10^-2kg)*(9.8m/s^2)= 0.784N

I don't know where to go from here though.

2. Sep 19, 2011

### flyingpig

Sammy if you are reading this, correct me if I am wrong lol.

If it is already in the air and it is hitting something, it kinda means there is a drag force (resistance force) negating gravity.

So you are only concern with the horizontal force.

You have distance and speed, you can find the acceleration.

3. Sep 19, 2011

### Capncanada

I only have the distance the arrow goes when it hits the target, I don't know how to apply it, I'm sorry.

4. Sep 19, 2011

### flyingpig

$$v^2 = v_0 ^2 + 2a\Delta x$$

5. Sep 19, 2011

### Capncanada

And how do I use this to find the force?

6. Sep 19, 2011

### flyingpig

F = ma

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