Question

14. A particle of mass 3 kg is moving along x-axis and its position at time t is given by equation x = (2t2 + 5) m.
Work done by all the forces acting on it in time interval t = 0 to t = 3 s is
(1) 144 J
(2) 72 J
(3) 108J
(4) 216 j​

Answer 1

Hey Dear,

◆ Answer - (4)

W = 216 J

● Explaination -

Velocity of the particle at 3 s is given by -

v = dx/dt

v = d(2t²+5)/dt

v = 4t

v = 4×3

v = 12 s

Acceleration of the particle during this motion will be -

a = (v-u)/t

a = (12-0)/3

a = 4 m/s²

Displacement of the particle during 3 s is -

s = ut² + 1/2 at²

s = 0×3 + 1/2 × 4 × 3²

s = 18 m

Now total work done during this motion is -

W = F.s

W = m.a.s

W = 3 × 4 × 18

W = 216 J

Therefore, work done by all forces is 216 J.

Thanks dear...

Answer 2

option 4 is correct answer I. e is 216 joule.