Inclined Plane Power

Move a load up a slope at constant speed. Change the angle and friction, then model the force and power needed from the motor.

Slope angle theta 25 deg

Friction coefficient mu 0.20

Mass m 40 kg

Speed up slope v 1.2 m/s

Weight mg-

Normal mg cos theta-

Down-slope mg sin theta-

Friction mu R-

Drive force at constant v-

Power against weight-

Power against friction-

Total motor power-

Constant speed means resultant force along the slope is zero. The motor must balance:
F_drive = mg sin(theta) + mu mg cos(theta)
P_weight = mgv sin(theta)
P_total = [mg sin(theta) + mu mg cos(theta)]v

weight mg mg sin(theta) normal reaction friction motor drive

Student Model Check

Enter your calculated values. Tolerance is 5 percent, so use sensible significant figures.

mg sin(theta) / N

friction / N

power vs weight / W

total power / W

Use theta in degrees on the slider, but convert to radians if your calculator needs it.