A rollercoaster with passengers has a mass of 2500 kg. This rollercoaster is powered to the top of a 25 m hill where it pauses for a moment at rest. It then plunges down hill to ground level where it enters a 15 m high vertical loop. After completing the loop it climbs a small hill and is brought to a stop at the station 4.0 m above ground level.
a. What is the speed of the rollercoaster at the top of the vertical loop?
b. What is the speed of the roller coaster as it enters the station but before it starts to slow down?