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A man of mass  jumps from an aeroplane as shown in Fig. He sees the hard ground below him and a lake at a distance  from the point directly below him. He immediately puts off his jacket (mass  and throws it in a direction directly away from the lake. If he just fails to strike the ground, find the distance (in  he should walk now to pick his jacket. (Neglect air resistance and take the velocity of man at the time of jump with respect to earth zero)



Question ID - 101430 | SaraNextGen Top Answer

A man of mass  jumps from an aeroplane as shown in Fig. He sees the hard ground below him and a lake at a distance  from the point directly below him. He immediately puts off his jacket (mass  and throws it in a direction directly away from the lake. If he just fails to strike the ground, find the distance (in  he should walk now to pick his jacket. (Neglect air resistance and take the velocity of man at the time of jump with respect to earth zero)

1 Answer
127 votes
Answer Key / Explanation : (3) -

(3)

To save himself, the man throws his jacket in opposite direction to the lake According to momentum conservation, he himself gets a velocity in the direction of the lake. During the motion as gravity is the only external force on the system (man plus jacket), centre of mass will not be displaced horizontally. Thus, centre of mass of the system falls vertically and when the man falls in the lake, jacket falls at a point such that the centre of mass of the man and the jacket will be directly below the point from where the man jumps)

As it is given that man falls at a distance  from this point, it implies that jacket will fall at adistance  in the opposite direction such that

 man has to travel a distance m to pick his jacket

127 votes


127