Why is gravity and example of a scientific law

Ahockey player of mass 82 kg is traveling north with a velocity of 4.1 meters per second he collides with the 76 kg player traveling east at 3.4 meters per second if the two players locked together momentarily in what direction will they be going immediately after the collision how fast will they be moving

What type of force holds atoms together in a crystal?

Why should the wavelength scale of spectroscope be calibrated