Question

Can you help me please?

Answer 1

See below:

Explanation:

a) I assume that `P_i` means initial momentum of the object:
momentum is given by `p=mv`
`p=4 times 8`
`p=32 N m^-1`
So the initial momentum of the object is `32 N m^-1`.

b) Change in momentum, or Impulse, is given by:

`F=(Deltap)/(Deltat)`

We have a force and we have a time, so therefore we can find the change in momentum.

`Deltap=-5 times 4`
`Deltap=-20 N m^-1`

So the final momentum is
`32-20=12 N m^-1`

c)
`p=mv` again, mass is unchanged but velocity and momentum has changed.
`12= 8 times v`
`v= 1.5 ms^-1`