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Grade 11Mechanics

A monkey of mass 20kg rides on a 40 kg trolley moving with constant speed of 8m/s along a horizontal track. If the monkey jumps vertically to grab the overhanging branch of a tree, the speed of the trolley after the monkey has jumped off is-?

Profile image of Vaibhav
12 Years agoGrade 11
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5 Answers

Profile image of India VK
ApprovedApproved Tutor Answer12 Years ago

8 m/s

Consider just the trolley as the system. Since the monkey jumps vertically, it does not exert any horizontal force on the trolley, so the trolley''s momentum remains unchanged. So its speed remains the same.

Profile image of Prakhar Tayal
12 Years ago

12m/s

60*8=40*x

x=12m/s

Conservation of momentum!

Regards,

Prakhar

Profile image of Vaibhav
12 Years ago
mass of monkey m=20 kgmass of trolley M =40 kgspeed of trolley with monkey v =8m/sBy principle of conservation of momentum,(m+M)v=MVV=(m+M)v/M  =(20+40)8/40  =12 ans
Profile image of rishabh
12 Years ago

Is the answer equals to 8/3

Profile image of Rashmi
7 Years ago
Since the monkey jumped off the trolley in a vertical direction which only provides a vertical force.. And as we know there is no contribution of vertical force in horizontal direction so the momentum of the trolley remains same, so the speed also remains same as before i.e. 8 m/s.
Hope you people understand