In the impulse approximation, .

(A) the forces between colliding objects can be neglected
(B) the external forces acting during a collision can be neglected
(C) the momentum of an object is zero
(D) the true impulse is approximated by a rectangular pulse

(B) the external forces acting during a collision can be neglected

Explanation:

Impulse is the product of force and time for which it acts. From Newton's second law, impulse is the change in momentum. In a collision of bodies, there is a change in velocity, either in direction or magnitude. Hence, there is a change in momentum and an impulse.

The forces between the object contribute to the impulse and cannot be neglected.

Since the forces act over a time interval, they may be time-dependent. In such cases, the impulse is not a rectangular pulse (which is the graph of a time-independent force).

Impulse calculations are performed in isolated systems. Hence, external forces are neglected.

it is the second option.

hi there!

out of the two, (b) precision would be more reasonable.   however, both a and b could be pretty reasonable.

-awesomerepublic   : )