I need help can someone answer this for me. It says model the force that would cause each velocity change.

1.what is where an object is located 2. what is how fast an objects speed is changing 3. what is how fast an object is moving

Abookcase has a mass of 38 kg and the coefficient of friction between it and the floor is 0.82 what is the maximum force of friction between the bookcase and the floor a 372n b 305n c 412n d 449n

Asolid cylinder and a cylindrical shell have the same mass, same radius, and turn on frictionless, horizontal axles. the cylindrical shell has light-weight spokes connecting the shell to the axle. a rope is wrapped around each cylinder and tied to blocks of equal masses that are held the same height above the ground. both blocks are released simultaneously. the ropes do not slip. which block hits the ground first? or is it a tie?