A weight lifter performed 200 J of work lifting a weight in 2 seconds. what was his power

A 0.0663 kg ingot of metal is heated to 241◦C and then is dropped into a beaker containing 0.395 kg of water initially at 25◦C. If the final equilibrium state of the mixed system is 27.4 ◦C, find the specific heat of the metal.

A concave lens is also called a diverging lens.

A bicycle tire has a radius of 0.23 m. The tire spins at a constant speed with a centripetal acceleration of 42 m/s2. What is the tangential speed of the tire? 3.1 m/s 6.5 m/s 9.7 m/s 14 m/s

In what sense are telescopes like time machines?

The combination of all of the force acting on an object is called the

Which wave characteristic has the unit hertz

A stretched spring has 5184 J of elastic potential energy and a spring constant of 16,200 N/m. What is the displacement of the spring?

A block of mass 1.3 kg is resting at the base of a frictionless ramp. A bullet of mass 50 g is traveling parallel to the ramp surface at 250 m/s. It collides with the block, enters it, and exits the other side at 100 m/s.

Metals are good thermal conductors - that is, when there is a temperature difference across their ends, they transfer energy very efficiently from the higher temperature end to the lower temperature end.

Some stars are so far away that their light hasn't reached Earth yet. A million years in the future, will the sources of light we see when we look up at night be the same? Why or Why not?