InterviewSolution
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InterviewSolution
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A trolley of initial mass `m_0` is kept over a smooth surface as shown in figure. A constant force F is applied on it. Sand kept inside the trolley drains out from its floor at a constant rate of `(mu)kg//s`. After time t find: (a) total mass of trolley and sand. (b) net force on the trolley. (c) velocity of trolley. |
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Answer» Correct Answer - A (a) Total mass of trolley and sand `m="initial mass-mass of sand drained out"` or `m=m_0-mut` (b) Let v is the velocity of trolley at time t. Then, velocity of sand drained out is also v or relative velocity is zero. Hence, no thrust force will act in this case. Therefore, `F_(n et)=F` (c) `F_(n et)=F` or `ma=F` or `m(dv)/(dt)=F` or `(m_0-mut)(dv)/(dt)=F` `:. int_0^vdv=int_0^t(Fdt)/(m_0-mut)` Solving this equation we get, `v=1/mulog_e((m_0)/(m_0-mut))` |
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