Refer to the adjacent figure. A variable force F is applied to a body of mass 6 kg at rest. The body moves along X-axis as shown. The speed of the body at x = 5 m and x = 6 m is ____ and ______ respectively.

Options

A. 0 m/s, 0 m/s
B. 0 m/s, 2 m/s
C. 2 m/s, 2 m/s
D. 2 m/s, 4 m/s

Answer

C

Explanation

Consider the figure given in the question Area of triangle XYZ,
`1/2 xx 4 xx = 8m^2`

Area of rectangle XYZ, `=1/2 xx 4 xx 4 = 8 m^2`
The speed of body at x = 5 m will be given by, Area of triangle + area of rectangle `8 + 4 = 12 m^2`
`12m^2 = 1/2mv^2`
`12 = 1/2 xx6xxv `
`24/6=4=v^2`
`v = 2m//s`
At x = 6 m, we have to find the speed. So, from x = 5 m to x = 6 m, speed will be constant as the force is zero, i.e., 2 m/s