Question

The potential energy of a particle of mass 5 kg moving in the x – y plane is given by, U = (–7x + 24y) J where x and y being in metre. If the particle starts from rest from origin, then speed of particle at t = 2s is :

• A. 5 m/s
• B. 14 m/s
• C. 17.5 m/s
• D. 10 m/s

Answer 1

Answer: (D)

10 m/s

Answer 2

Sol. Q = – = –[–7 + 24]

\ F = $\sqrt { 7 ^ { 2 } + 24 ^ { 2 } }$ = 25 NŽ a = F/m = 25/5 = 5 m/s²

Q v = u + at

= 0 + 5 × 2 = 10 m/s