A body of mass 3 kg acted upon by a constant force is displaced by S meter, given by relation S=1/3t², where t is in second. Work done by the force in2 seconds

Options

(a) 8/3 J
(b) 19/5 J
(c) 5/19 J
(d) 3/8 J

Correct Answer:

8/3 J

Explanation:

S = (1/3) t²; v = dS / dt = (2/3) t
a = d²S / dt² = 2/3
F = ma = 3 × (2/3) = 2N
Work = 2 × (1/3) t²
At t = 2 seconds
.·. Work = 2 × (1/3) × 2 × 2 = (8/3) J