Answer: The magnitude of impulse acted on the cart will be 1200 kg.m/s
Step-by-step explanation:
Impulse is defined as the product of mass of the object and the change in its velocity. It is basically the change in momentum of the body.
Mathematically,

where,
J = Impulse
m = mass of the object
= change in the velocity
We are given:

Putting values in above equation, we get:

Hence, the magnitude of impulse acted on the cart will be 1200 kg.m/s