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roovid
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work, energy, power helpp
question:
A man of mass 70kg rides a bicycle of mass 15kg at a steady speed of 4ms-1 up a road which rises 1m for every 20m of its length. what power is the cyclistdeveloping if there is a constant resistance to motion of 20N?
Ans: 250W
My sol'n so far:
Sin∅ = 1/20
in 1second object moves 4m
therefore
1/20 = x/4
x = 0.2m
Ep = mgh
=85(10)(0.2)
=170
Ek=0.5mv2
= 0.5(85)42
= 680
Ek+Ep= 170 + 680
= 850
work done by resistive force = fs
= 20(4)
= 80
Wcyclist= [ Ep + Ek ] + Wresistive force
= 680 + 80
stuck
please help
where am i going wrong
question:
A man of mass 70kg rides a bicycle of mass 15kg at a steady speed of 4ms-1 up a road which rises 1m for every 20m of its length. what power is the cyclistdeveloping if there is a constant resistance to motion of 20N?
Ans: 250W
My sol'n so far:
Sin∅ = 1/20
in 1second object moves 4m
therefore
1/20 = x/4
x = 0.2m
Ep = mgh
=85(10)(0.2)
=170
Ek=0.5mv2
= 0.5(85)42
= 680
Ek+Ep= 170 + 680
= 850
work done by resistive force = fs
= 20(4)
= 80
Wcyclist= [ Ep + Ek ] + Wresistive force
= 680 + 80
stuck
please help
where am i going wrong
Last edited: