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a. A rail road car of mass M is moving w...

a. A rail road car of mass M is moving without friction on a straight horizontal track with a velocity ct. A man of mass m lands on it normally from a helicopter. What will be the new velocity of the car? ltbgt b. If now the man begins to run on it with speed um with respect to car in a direction opposite to motion of the car, what will be the new velocity of the car?

Text Solution

Verified by Experts

Let `v_(1)` be the new velocity of the car. Then according to the principle of conservatioin of linear momentum
`Mu=(M+m)v_(1)`
`implies v_(1)=m/(M+m)u`…………..i
b. Let `v_(2)` be the new velocity of the car relative to the earth, then velocity of the man relative of the earth `=(v_(2)-v_(rel))`
`:. v_(2)=v_(1)+(mv_(rel))/(M+m)`
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Knowledge Check

  • A man of mass m stands on a long flat car of mass M , moving with velocity V.If he now begins to run with velocity u, with respect to the car , in the same direction as V, the the velocity of the car will be

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    `V-m u //(m+M)`
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    `V+m u//(m+m)`
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    `V-u(M-m)//(M+m)`

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