2. An 800-g bird has 47.0 J of gravitational potential
energy when it is perched high up in a tree.
Calculate the bird's vertical height from the ground.

"an open tank has the shape of a right circular cone. the tank is 6 feet across the top and 5 feet high. how much work is done in emptying the tank by pumping the water over the top edge? note: the density of water is 62.4 lbs per cubic foot."

What is the angular momentum of the bar about the axle?

If two students are running down the hall toward each other, trying to get to class, and they have the same mass and acceleration, what will happen when they collide? will their forces cancel out or will each one experience a reaction?