Look at the picture below. the boy is swinging back and forth on the swing. at which point is the potential energy of a swing the greatest? point a (top) point b (halfway down) point c (bottom) point d (halfway up)

In a system, when potential energy decreases, then entropy also decreases. true false

Polly is pushing a box across the floor with a force of 30 n. the force of gravity is –8 n, and the normal force is 8 n. which value could describe the force of friction if polly could not move the box?

Two point charges are on the y axis. a 3.90-µc charge is located at y = 1.25 cm, and a -2.4-µc charge is located at y = −1.80 cm. (a) find the total electric potential at the origin. v (b) find the total electric potential at the point whose coordinates are (1.50 cm, 0). v