5 sin(15º) gives the vertical displacement (work against gravity)
cosine gives the horizontal displacement
How much work is done by the orderly pushing a 85 kg person up a 5 m ramp inclined at an angle of 15° to the horizontal?
I did W = (85)(9.8)(5)cos15, but to get the correct answer you are supposed to use
(85)(9.8)(5)sin15 instead.
Why do we have to use sin?
2 answers
He is doing work against gravity, vertical. The ramp is at75 deg to the vertical.
work=85(9.8)5cos75 = if you wish...85*9.8*5sin15
work=85(9.8)5cos75 = if you wish...85*9.8*5sin15
2 answers