Question

A 2 kg object initially moving with a constant velocity is subjected to a force of magnitude F in the direction of motion. A graph of F as a function of time t is shown. What is the increase, if any, in the velocity of the object during the time the force is applied?

(A) 0 m/s 

(B) 2.0 m/s 

(C) 3.0 m/s 

(D) 4.0 m/s 

(E) 6.0 m/s

Answer 1

Correct option is (D) 4.0 m/s

The area under the F-t graph will give the impulse which is equal to the momentum change. With the momentum change we can find the velocity change.

\(\triangle p = \frac 12 (a + b)h\)

\(= \frac 12 (3 + 5)2\)

\(\triangle p = 8\)

\(\triangle p = mv\)

\(8 = 2v\)

\(v = 4 m/s\)