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Grade 10Mechanics

gravel is dropped into a conveyer belt at rate of 0.5kg/sec. the xtra force needed to keep the belt moving at 2m/s is?

Profile image of kedar joshi
15 Years agoGrade 10
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2 Answers

Profile image of AKASH GOYAL AskiitiansExpert-IITD
ApprovedApproved Tutor Answer15 Years ago

Dear Kedar

The net force should be defined as the rate of change of momentum
here v is constant hence dv/dt is 0
dm/dt= 0.5 kg/sec, v=2m/s
hence extra force required= v*dm/dt = 2*0.5 = 1N

All the best.

AKASH GOYAL

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Profile image of deeksha sharma
15 Years ago

This is the case of same velocity and changing mass.

So F=-u*(dm/dt)= 2*0.5=1N           <F-dp/dt=d/dt(mv)=v(dm/dt)+m(dv/dt)= v*(dm/dt)    bcoz vel remains constt, dv/dt=0>

 So a force equal to newton is required.

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