# Impulse and impulsive force and momentum

1. Jun 21, 2011

### stupif

1)anyone tells me what is the differences between impulse and impulsive force??

2) impulsive force = force X time
momentum = mass X change in velocity
impulse force = momentum. i know why but i dont understand why impulsive force is same as momemtum, if i want to decribe something about the punch of the frighter, i should say impulsive force ?? and when i should say it is momentum not impulsive force??

2. Jun 21, 2011

### WannabeNewton

$$J = F\Delta t = ma\Delta t = m\frac{\Delta v}{\Delta t}\Delta t = m\Delta v = \Delta p$$ where J is the impulse. Impulse is the change in momentum not simply momentum =D.

3. Jun 21, 2011

### stupif

for impulse formula is (mv-mu)/t ???

4. Jun 21, 2011

### WannabeNewton

what is u in your formula?

5. Jun 21, 2011

### stupif

u= initial velocity, v=final velocity

6. Jun 21, 2011

### WannabeNewton

Your formula is fine except there is no factor of 1/t. It is simply, in accordance with your notation, J = mv - mu.

7. Jun 21, 2011

### Superstring

Impulse is the change in momentum, and is given the symbol J.

Impulsive force is the force that acts to create the impulse, and has the symbol F.

$$\mathbf{J}=m\mathbf{v}-m\mathbf{v_0}=\mathbf{F}t$$

So an equation for impulsive force would be what you posted above:

$$\mathbf{F}=\frac{m\mathbf{v}-m\mathbf{v_0}}{t}$$

8. May 6, 2012

### Koya.NeutronD

example for impulse and impulsive force???