If I hold an .63kg basketball 2 meters above the ground, how much potential energy does it have?
If I drop the basketball from this height, how
much kinetic energy would it have right before it hits the floor?

Zeros that follow non-zeros numbers and are also to the right of a decimal point are significant

Large electric fields in cell membranes cause ions to move through the cell wall. the field strength in a typical membrane is 1.0 x 10 7 n/c. what is the magnitude of the force on a calcium ion with charge +e? what is its acceleration? is it possible for a particle with the same charge as as calcium to have a different acceleration if placed at this location? what would change the acceleration: mass of the particle? diameter of the particle?

The force needed to overcome static friction is usually less than that needed to overcome kinetic friction.true or false?