How do you do this? my teacher is the worst and i need to know how to solve these. just me solve the first one.

Acricket ball of 70g moving with a velocity of 0.5 m/s is stopped by a player in 0.5s what is the force applied to stop the ball

Avalue that describes how heavy an object is and is related to the force of gravity is

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?