Unbalanced forces opposing motion between touching surfaces. what is that called?

Rita throws a ball straight up into the air and catches it at the same position from which she threw it. The ball has 18 J of mechanical energy when it leaves her hand.

You're a production engineer in a cookie factory, where mounds of dough drop vertically onto a conveyor belt at the rate of one 12-g mound every 2s. You're asked to design a mechanism that will keep the conveyor belt moving at a constant 50cm/s.

Where else could Snell's law be useful in determining the path of a light ray in your everyday life?

In most cases a structure can have only one service true or false

5. What do the four controversial elections tell us about the Electoral College system? Fair, Broken, Unfair, Rare, etc.?

Without the force of friction, people would not be able to walk.

A truck covers 40.0 m in 8.50 s while smoothly slowing down to a final speed of 2.80 m/s. (a) find its original speed. (b) find its acceleration.

The matter that makes up a planet is distributed uniformly so that the planet has a fixed, uniform density.

3. If the potential difference is 120 volts and the resistance is 60 ohms, what is the current?

Which of galileo's observations most strongly supported a heliocentric cosmology? the phases of venus?