Answer:
Equal to change in momentum of larger mass.
Step-by-step explanation:
We are given that
Two difference masses .
Force act on both masses for the same length of time.
We have to find the change in momentum of the smaller mass.
Let M and m are two masses
M>m
We know that
Change in momentum for large mass=

Change in momentum for small mass=

Because Force and length of time are same for both masses .
Hence, the change in momentum of smaller mass is equal to change in momentum of larger mass.