| Alice and
her pet alligator are strolling at a constant velocity on the sands of
the Egyptian desert. Alice is pulling on the handle of the wagon with a
force of 90 N, and the handle makes an angle of 30° with the horizontal.
If the wagon weighs 60 N, the alligator weighs 220 N, Alice weighs 500 N, the Earth is round, and the desert is hot, what is the magnitude of the force of friction between the wagon and the hot desert sands? |
All the problem asks for is the friction
force. Since the velocity is constant, we know the net force is zero. Therefore
the friction force must be balancing the horizontal component of the force
along the wagon handle. So,
F = (90 N)cos 90° = 77.9 N. |