A 10 kg box initially at rest is pulled with a 50 N horizontal force for 4 m across a level surface. The force of friction acting on the box is a constant 20 N. How much work is done by the force of friction?

Light from a fluorescent lamp is observed through a cloud of cool nitrogen gas. Again, two students are having a discussion about the kind of spectra that they would see.

A 82.1 kg person stands on a scale. what normal force does the scale exert on him? (Unit = N)

How much force does the 2.0 kg block exert on the 1.0 kg block?

Materials that allow the charges of an electric current to move freely through them are called a. insulators. b. conductors. c. resistors. d. magnets.

18. What is the kinetic energy of an object that has a mass of 30 kilograms and moves with a velocity of 20 m/s? A. 6,000 J B. 5,880 J C. 2,940 J D. 12,000 J

How long did it take to reload a rifle during the 18th 19 century?

Oil flows upward in the wick of a lantern because of the liquid property called A. meniscusity. B. capillarity. C. density. D. viscosity.

A high-mass star has more "fuel" than a low-mass star. which lives longer? why?

Suppose that, while lying on a beach near the equator of a far-off planet watching the sun set over a calm ocean, you start a stopwatch just as the top of the sun disappears. you then stand, elevating your eyes by a height h = 1.

Suppose you want to know if the color of peoples hair affects how warm it can keep their heads. describe the skills you would use to conduct an experiment to test your inquiry