How big is observable universe? How do we know that?

A crane does 62,500 joules of work to lift a boulder a distance of 25.0 meters. How much did the boulder weight

Two carts with masses of 4.2 kg and 3.2 kg move toward each other on a frictionless track with speeds of 5.4 m/s and 4.5 m/s, respectively. The carts stick together after colliding head-on. Find their final speed. Answer in units of m/s.

The launching velocity of a missile is 20.0 m/s, and it is shot at 53º above the horizontal. What is the vertical component of the velocity at launch?

How would you explain social control to someone who has no idea about our society?

A linear accelerator uses alternating electric fields to accelerate electrons to close to the speed of light.

Two objects have the same momentum. Do the velocities of these objects necessarily have (a) the same directions and (b) the same magnitudes? Give your reasoning in each case.

If you keep voltage constant and increase resistance resistance, what happens to current?

A scene in a movie has a stuntman falling through a floor onto a bed in the room below. The plan is to have the actor fall on his back, but a researcher has been hired to investigate the safety of this stunt.

During energy transformation, all energy systems: are a. 100 percent efficient b. lose energy c. gain heat energy d. create energy

An apple with a mass of 0.95 kilograms hangs from 3.0 meters above the ground. What is the potential energy of the apple