# Homework Help: Impulse/Momentum physics question

1. Nov 15, 2004

### sweetness

Hey just wondering if someone could help me out, im stumped :grumpy:

A slingshot exerts an average horizontal force of 80 newtons for 0.11 seconds on a stone weighing 3.2 newtons. Find
a) the average acceleration of the stone
b) The impulse delivered to the stone
c) The speed of the stone
d) The resulting momentum of the stone

2. Nov 15, 2004

### Gokul43201

Staff Emeritus
Sweetness,

Do you know what the formulas (equations) are, for any of those quantities ? Surely they are in your text.

Give it your best shot, and we'll tell you what's wrong.

3. Nov 15, 2004

### sweetness

i know the equation to find mometum - p=m*v and also the impulse is equal to the momentum, the units for momentum are kgm/s and Impulse is N.S, but i dont know about average acceleration
i think for c) the formula is V=I/mass of stone
but i really have no clue where to start!!

4. Nov 17, 2004

### Silimay

Impulse also equals average force multiplied by duration (in seconds) the force was applied. Momentum = Mass * Velocity.

5. Nov 17, 2004

### Diane_

And impulse is not equal to momentum, it's the change in momentum.

6. Nov 17, 2004

### HallsofIvy

Since you are given Force and asked about Acceleration, do you know
"F= mA"?

7. Nov 18, 2004

### Raza

Is this how you solve it?

$$A)$$
$$F=MA$$

$$80=3.2A$$

$$A=80/3.2$$

$$A=25m/s^2$$

$$B)$$
$$Vf=(Vi)(T)+\frac{1}{2}(A)(T)^2$$

$$Vf=(0)(0.11)+\frac{1}{2}(25)(0.11)^2$$

$$Vf=0+0.15125$$

$$Vf=0.15125$$

$$V=Vf+Vi$$

$$V=0.15125+0$$

$$V=0.15125$$

$$I=VM$$

$$I=(0.15125)(3.2)$$

$$I=0.484$$

I have no idea how to do C and D.

Last edited: Nov 18, 2004