A planet moves in a circular orbit of radius R with a momentum of magnitude
Ipl. What is the magnitude of the
ang ular momentum of the planet about
the center of the orbit?
1. the magnitude of the angular
momentum is |L|=R^2|p|
2. the magnitude of the angular
momentum is |L|=R|p|^2
3. the magnitude of the angular
momentum is |L|=R|p|
4. the magnitude of the angular
momentum is |L|=mv^2/R

In what direction does an applied force move an object

Two forces produce equal torques on a door about the door hinge. the first force is applied at the midpoint of the door; the second force is applied at the doorknob. both forces are applied perpendicular to the door. which force has a greater magnitude?

It's a snowy day and you're pulling a friend along a level road on a sled. you've both been taking physics, so she asks what you think the coefficient of friction between the sled and the snow is. you've been walking at a steady 1.5m/s, and the rope pulls up on the sled at a 32 ∘ angle. you estimate that the mass of the sled, with your friend on it, is 65 kg and that you're pulling with a force of 80 n .