What force causes riders to feel heavy and weightless on a roller coaster?
a. the force of gravity
c. the normal force
b. a combination of air resistance and friction
d. none of the above.

The substances that are necessary for producing of certain hormones and that store and transport vitamins

It's a snowy day and you're pulling a friend along a level road on a sled. you've both been taking physics, so she asks what you think the coefficient of friction between the sled and the snow is. you've been walking at a steady 1.5m/s, and the rope pulls up on the sled at a 32 ∘ angle. you estimate that the mass of the sled, with your friend on it, is 65 kg and that you're pulling with a force of 80 n .

Two positive charges are equal. which has more electric potential energy?