A 40-Kg Block Slides Along a Frictionless Surface with a Constant

Multiple Choice

A 4.0-kg block slides along a frictionless surface with a constant speed of 5.0 m/s as shown. Two seconds after it begins sliding, a horizontal, time-dependent force is applied to the mass. The force is removed eight seconds later. The graph shows how the force on the block varies with time.
-What is the magnitude of the total impulse of the force acting on the block?

A) 20 N . s
B) 42 N . s
C) 48 N . s
D) 54 N . s
E) 60 N . s