A440 kg roller coaster car is going 26 m/s when it reaches the lowest point on the track. if the car started from rest at the top of a hill, how much higher was that point on the track than the lowest point? (use g = 9.80 m/s2, and ignore friction.)

choices are these:
17 m23 m34 m69 m

20) what is a magnetic field? 21) in which direction do magnetic field lines always point? 22) sketch a diagram showing how a plotting compass points around a 23) name two magnetic poles that will: a) attract each other b) repel each other. 24) explain why you can use a compass to navigate. 25) what's an electromagnet? 26) list two ways to increase the strength of an electromagnet. 27) the wire in a simple motor feels a force when a current flows through it. why is this? i need answers to check mine