## Suppose the sun shrank in size but its mass remained the same. what would happen to the orbit of earth?

October 15, 2019// Blog//

Impulse is the change in momentum.

All we need is the momentum before and after.

**Momentum = (mass) x (speed)**

**Before: ** = (80 kg) x (4.7 m/s) = 376 kg-m/s

**After: ** = (80 kg) x (3.4 m/s) = 272 kg-m/s

Change in momentum = (376 – 272) = **104 kg-m/s**

Notice that when you work with impulse, you’re USUALLY calculating

(force) x (time).

The force is in Newtons, and the time is in seconds,

so the impulse is usually in units of

Newton-seconds .

So how can I say that impulse and change of momentum are

the same thing ? Am I trying to pull a fast one on you ?

Remember that 1 Newton is 1 kg-m/s²

So (force) x (time)

= (Newton) x (second)

= (kg-m/s²) x (second) = **kg-m/s** .

and Momentum = (mass) x (speed) = **(kg) x (m/s)**

The units of impulse are the same as the units of momentum !

So when you give an object some impulse, you give it exactly

that much momentum.