A body with mass `1kg` moves in one direction in the presence of a force which is described by the potential energy graph. If the body is releasd from rest at `x=2 m`, than its speed when it crosses `x=5 m`, is (Neglect dissipative forces).

Options

A. zero
B. `1 ms^(-1)`
C. `2sqrt(2)ms^(-1)`
D. `3 ms^(-1)`

Answer

C

Explanation

Let at `x = 2 m, U = U_(2)`
`(10 - U_(2))/(2 - 1) = (10 - 0)/(3.5 - 1) implies U_(2) = 6J`
`(KE + PE)_(x = 2m) = (KE + PE)_(x = 5m)`
`implies 0 +6 = (1)/(2) (1) v^(2) + 2 implies v = 2sqrt(2)m//s`