Estimate the power required to operate the tow

[Edwardo_Elric]

Homework Statement

A ski tow is operated on a 20 degree slope of lenth 300m. The rope moves at 12.0km/h, and power is provided for 70 riders at one time with an average mass per rider of 65kg. Estimate the power required to operate the tow.

Homework Equations

P = Work / t
P = F * v

The Attempt at a Solution

60kg * 70 riders = 4550kg
Solving for time:
V = 12km/h = 3.33m/s

t = d / V
= 300m / 3.33m/s
= 90.09s

P = (F * d) / t
P = ((4550kg)(9.8m/s^2)( 300m))/(90.09s)
= 148484.8485 watts

I don't see what is the angle used for
maybe for another component of force? or is it no use?

 

[learningphysics]

You need the acceleration along the slope to be zero to keep the riders moving at a constant velocity along the slope... The ski tow exerts a force along the slope.

Also, you can directly use F*v for power, instead of using time and distance...

 

[Edwardo_Elric]

0 = F - wsin(theta)
F = (4550kg)(9.8m/s^2)sin(20) << so force

thanks

 

[learningphysics]

0 = F - wsin(theta)
F = (4550kg)(9.8m/s^2)sin(20) << so force

thanks

yup. then using this force F*v gives power.