A black of mass 4.0 kg starts from rest and slides down a surface which corresponds to a quarter of a circle of 2.0 m radius.1)if the curved surface is smooth, find the speed at the bottom.2)if the speed at the bottom is 2.0m/s, calculate the energy dissipated due to friction in the descent.3)after the block reaches the horizontal with a speed of 2.0m/s it slides to a stop in a distance of 1.5m . Calculate the frictional force acting on the horizontal surface. Take g=10m/s2.
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Expert's answer
2020-03-04T10:07:24-0500
1) According to law of conservation of energy, in case without friction the terminal velocity at the end of the curve will be
mgh=21mv2,v=2gh=2gR=2⋅9.8⋅2=6.26 m/s.
2) Write law of conservation of energy:
mgh=Afriction+21mu2,Afriction=m(gR−21u2)=70.4 J.
3) The only force that affects block's motion is the force of friction. According to Newton's second law, the force of friction will be a net force:
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