A piece of Styrofoam has a charge of -0.004 C and is placed 3.0 m from a piece of salt with a charge of- C. How much electrostatic force is produced ?

If the speed of a particle triples ,by what factor does its kinetic energy increase?

Which statement is true? a. kepler's laws apply only to the motion of earth. b. kepler's laws can be used to predict eclipses. c. kepler's laws are true for a central force that is directly proportional to distance. d. kepler's laws can be deduced from newton's laws of motion and gravity.

What are similarities and differences of reflection, refraction, diffraction and absorption?