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Figure shows a flat car of mass `M` on a frictionless road. A small massless wedge is fitted on it as shown. A small ball of mass `m` is released from the top of the wedge, it slides over it and falls in the hole at distance `l` from the initial position of the ball. Find the distance the flat car moves till the ball gets into the hole. |
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Answer» When the bell falls into the hole, with respect to the flat car, the bail travels a horizontal distance `l`. During this motion, to conserve momentum and to maintain the position of centre of mass, the car moves towards left, say by a distance `x`. Thus, the total distance travelled by the ball towards right is `(l-x)`. As centre of mass remains at rest, the change in mass moments of the two (ball and car) about any point must be equal to zero. Hence `m(l-x)=MXimpliesm=(ml)/(M+m)` |
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