1.

Under the action of a force, a `2 kg` body moves such that its position x as a function of time is given by `x =(t^(3))/(3)` where x is in metre and t in second. The work done by the force in the first two seconds is .A. `1.6 J`B. `16 J`C. `160 J`D. `1600 J`

Answer» Correct Answer - B
`v = (dx)/(dt) = (d)/(dt) ((t^(3))/(3)) = t^(2)`
Where `t = 0` When `t = 2`, then `t = 4 m//s`
Work down in first two second = change in KE
`W = (1)/(2)m [(4)^(2) - (0)^(2)] = (1)/(2) 2 xx 16 = 16`


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