Johnny kicked a football from a hill 20 meters tall. The ball leaves at a 45.0 degree angle with an initial velocity of 30.0 m/second. How many seconds was the ball in the air? Report your answer to 3 sig figs. Seconds

Aperson stands on a platform, initially at rest, that can rotate freely without friction. the moment of inertia of the person plus the platform is ip. the person holds a spinning bicycle wheel with its axis horizontal. the wheel has moment of inertia iw and angular velocity ωw. take the ωw direction counterclockwise when viewed from above. part a what will be the angular velocity ωp of the platform if the person moves the axis of the wheel so that it points vertically upward?

Amira pulls a 3 pound wagon 4 feet. how much work has she done?

What are the starting materials for nuclear fission? two small nuclei two large nuclei a neutron and a large nucleus a neutron and a small nucleus