# A block of mass m, lying on a smooth horizontal surface, is attached to spring (of negligible mass) of spring constant K. The other end of the spring is fixed, as shown in the figure.  The block is initially at rest in its equilibrium position.  If now the block is pulled with a constant force F, the maximum speed at the block is: a. b. c. d. ## Question ID - 50044 :- A block of mass m, lying on a smooth horizontal surface, is attached to spring (of negligible mass) of spring constant K. The other end of the spring is fixed, as shown in the figure.  The block is initially at rest in its equilibrium position.  If now the block is pulled with a constant force F, the maximum speed at the block is: a. b. c. d. 3537

Maximum speed is at mean position (equilibrium). F=kx

x= Wp + Wsp = KE

F(x) kx2 = mv2−0

F k mv2 Vmax= Next Question :

There charges +Q, q+Q are placed respectively, at distance, o, d/2 and d from the origin, on the x-axis.  If the net force experienced by +Q, placed at x=0, Ls Zero, then value of q is:

 a. +Q/2 b. −Q/2 c. −Q/4 d. +Q/4 