A srping lies along the x-axis attached to a wall at one end and a block at the other end. The block rests on a friction less surface at `x=0`. A force of constant magnitude F is applied to the block that begins to compress the spring, until the block comes to a maximum displacement `x_(max)`.

During the displacement, which of the curves shown in the graph best represents the kinetic energy of the block?

Options

A. (a) 1
B. (b) 2
C. (c) 3
D. (d) 4

Answer

C

Explanation

Applying work-energy theorem on the block for any compression x,
`W_(ext)+W_g+W_(spri ng)=DeltaKE`
`F_x+0-1/2Kx^2=1/2mv^2`
KE versus x graph is an inverted parabola.