Please help with physics HW

2 1. A skateboarder is at rest at the top of an 18m high hill with 14600 ] of potential energy: a. What is the skateboarder's kinetic and potential energy at the top of the hill? b. What is the skateboarder's kinetic and potential energy half-way down the hill? c. What is the skateboarder's kinetic energy and potential energy when he reaches the bottom the of the hill? d. What is the mass of the skateboarder? e. What is the velocity of the skateboarder at the half-way point? 2. A 12 kg block slides down a frictionless 25m ramp with an incline of 32 degrees: a. What is the total mechanical energy for this system? b. What is the potential and kinetic energy when the block is half-way down the ramp? c. What is the velocity of the block at the bottom of the ramp? d. What is the acceleration of the block