V = 12.5km/h = 12500m/3600s. = 3.47 m/s.
P = 55F*V = 55*mg*V = 55*68*9.8*3.47 =
127.2 Joules/s = 127.2 Watts.
A ski tow operates on a slope of angle 14.9∘ of length 320m . The rope moves at a speed of 12.5km/h and provides power for 55 riders at one time, with an average mass per rider of 68.0kg .Estimate the power required to operate the tow.
5 answers
Correction: Change 127.2 J./s to
127.2 kJ/s = 127.2 KW.
127.2 kJ/s = 127.2 KW.
127.2W
133477.338
o lift the skiers, the rope must do positive work to counteract the negative work developed by the component of the gravitational force acting on the total number of skiers, Frope=Nmgsinα.
SET UP: P=F∥v=Fropev
EXECUTE: Prope=Fropev=[+Nmg(cosϕ)]v.
Prope=[(49riders)(74.0kg)(9.80m/s2)(cos75.2)][(12.6km/h)(1m/s3.60km/h)].
Prope=3.2×104W=32kW.
SET UP: P=F∥v=Fropev
EXECUTE: Prope=Fropev=[+Nmg(cosϕ)]v.
Prope=[(49riders)(74.0kg)(9.80m/s2)(cos75.2)][(12.6km/h)(1m/s3.60km/h)].
Prope=3.2×104W=32kW.