Recent content by Tim Wu

Oh yeah! Ek=1/2*m*v^2, and v = p/m, therefore Ek= p^2/2m. Since p is the same for car and Earth but the Earth's mass is way bigger the kinetic energy gained by Earth wud be much lower! So would option c be right?

I find this problem kind of tricky. I think it must be a, since a change in momentum of the car causes the same change in momentum of the earth.