. 4. A 250 kilogram cannon launches a 30 kilogram cannon ball at a velocity of 20 m/s. What is
the recoil velocity of the cannon?

Energy is the ability to do work which measures what

If it takes a planet 2.8 x 10^8 s to orbit a star with a mass of 6.2 x 10^30 kg what is the average distance between the planet and the star

The charge on an electron is 1.60218 × 10−19 c and its mass is 9.10939 × 10−31 kg. how strong a magnetic field must be experienced by the electron if its path is a circle of radius 5.5 cm? answer in units of t.