Given: each railroad car has a mass of 52000 kg. three coupled railroad car moving with a speed of 3.7 m/s collide and couples with four other coupled railroad cars moving in the same direction with an initial speed of 2.4 m/s. what is the speed of all seven cars after the collision? answer in units of m/s.

Ablock of steel has a density of 0.29lbs per cubic inch. if the block has dimensions of 1 inch by 1 inch by 3 inches, what is its weight? a. 0.29lbs b. 0.58lbs c. 0.87lbs d. 1lbs

Two identical stars with mass m orbit around their center of mass. each orbit is circular and has radius r, so that the two stars are always on opposite sides of the circle. (a) find the gravitational force of one star on the other. (b) find the orbital speed of each star and the period of the orbit. (c) how much energy would be required to separate the two stars to infinity?

Achild has maximum walking speed of 1.6 m/s. what is the length of the child's legs? 0.26 m