Question

A body of mass 0.5 kg travels on straight line path with velocity v = (3x2 + 4) m/s. The network done by the force during its displacement from x = 0 to x = 2 m is

• A. 64 J
• B. 60 J
• C. 120 J
• D. 128 J

Answer 1

Answer: (B)

60 J

Answer 2

v = 3x2 + 4
at x = 0, v1 = 4 m/s
x = 2, v2 = 16 m/s
⇒Work done = △ kinetic energy
W= $\frac{1}{2}$m (v22-v12) W=$\frac{1}{2}$×$\frac{1}{2}$(162-42) W=$\frac{1}{4}$×(256-16) W=$\frac{240}{4}$=60J