A roller coaster car of mass 200 kg starts from rest at the top of a hill 20 m high and rolls down to ground level. From there it starts into a vertical loop. Exactly at the top of the loop it is 15 m high and the radius of curvature of the track is 5.0 m. Assuming negligible friction and air resistance, what is the magnitude of normal force acting on the car at the top of the loop?

The pressure proportional to the area a- inversely b- directly c- increase d-decrease

I'm thinking it's 2 you are asked to explain the earth's magnetic field. which is the best reply? 1. the earth's magnetic south is similar to the north pole of a magnet. 2. the earth's core has a strong magnetic charge similar to the south pole of a magnet. 3. the earth's geomagnetic south is similar to the south pole of a magnet. 4. the earth's magnetic charge is not centered at either pole; it varies based on location.

The law of the conservation of momentum says that the total momentum of any closed and isolated system cannot