The 500 kg car travelling at 25 m s-1 collides head-on with another of mass 800 kg travelling at 18 m s-1 in the opposite direction and they move together after impact. What is the magnitude of their velocity just after impact and in what direction do they move off?

Asled is being held at rest on a slope that makes an angle θ with the horizontal. after the sled is released, it slidesa distance d1 down the slope and then covers the distance d2 alongthe horizontal terrain before stopping. find the coefficient ofkinetic friction μk between the sled and the ground, assumingthat it is constant throughout the trip. find the coefficient of kinetic frictionμk. express your answer in terms of someor all of the variables d1, d2, and θ.

What would be the radius of the earth if it had its actual mass but had the density of nuclei? express your answer to two significant figures and include the appropriate units.

The path of a satellite orbiting the earth causes it to pass directly over two tracking stations a and b, which are 51 miles apart. when the satellite is on one side of the two stations, the angles of elevation at a and b are measured to be 87 degrees and 84 degrees, respectively. (a) how far is the satellite from station a? (b) how high is the satellite above the ground?