physics questions?

Question

1) How do you find the mass of an object only knowing the speed of the object and the kinetic energy of the object
2)how do you find the speed of an object only knowing the kinetic energy and the mass
3)How to you find an objects speed at the end of something (a hill for example) only knowing the vertical drop and the mass of the object

Answer 1

KE= .5*m*v^2

1) m=2*KE/v^2

2)v=sqrt(2*KE/m)

3) PE=m*g*h
without friction
.5*m*v^2=m*g*h
divide out mass
v=sqrt(2*g*h)

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