A mechanical device requires 420 J of work to do 230 J of work to lift a crate. What is the efficiency of the device? 190% 0.5% 183% 55%

You are explaining to friends why astronauts feel weightless orbiting in the space shuttle, and they respond that they thought gravity was just a lot weaker up there.

The ___ of immersion oil is the same as glass

Which of the following statements are true? Check all that apply. A. Earth's geographic south pole is also a magnetic south pole. B. Scientists have evidence that single isolated magnetic poles, called magnetic monopoles, exist. C.

An l-c circuit has an inductance of 0.450 h and a capacitance of 0.200 nf. during the current oscillations, the maximum current in the inductor is 1.40 a.

The commonality between Becquerel and the Curies is their work with

Gravity is the force by which a planet or other body draws objects toward its center. The force of gravity keeps all of the planers in orbit around the Sun.

What wave-like property of light causes it to bend when encountering an opening? A. Reflection B. all the above c. Refraction d. none of the above e. diffraction

Which of the following statements describe sliding friction? Select all that apply. 1.) a force that causes an object to increase speed 2.) a force in which one of the objects involved must be a liquid or a gas 3.

What do a broken rode and a volcano eruption have in common

What is the input of energy for a device that provides 50 units of useful energy and has an efficiency of 0.55?