An ideal machine has an efficiency of 100%

A factory worker moves a 30.0 kg crate a distance of 4.50 m along a level floor at constant velocity by pushing horizontally on it. the coefficient of kinetic friction between the crate and the floor is 0.250.

In his proposed model of the atom, JJ Thomson imagined the atom contained

The term "cosmic abundance" is made up primarily of what gases?

If the mass of a material is 104 grams and the volume of the material is 16 cm3, what would the density of the material be?

If a student walks 3 blocks/min, how long will it take him to walk 10 blocks?

Which of Newton's laws, when combined algebraically with his law of universal gravitation, can be used to calculate Earth's mass? A) first B) second C) third

Why does a balloon filled with helium rise while a balloon filled with an equal volume of average atmospheric air does not? A. Helium has no mass, but air does. B. Helium increases the balloon's mass more than air. C.

Consider the following controls in an automobile in motion : gas pedal, brake, steering wheel. what are the controls in this list that cause an acceleration of the car?

What material are oil pipelines made from?

3/129 A 175-lb pole vaulter carrying a uniform 16-ft, 10-lb pole approaches the jump with a velocity v and manages to barely clear the bar set at a height of 18 ft. As he clears the bar, his velocity and that of the pole are essentially zero.