Alisa, a skateboarder, is riding down a hill. If Alisa and the skateboard are considered a single object, what forces are acting on her? check all that apply

push

gravity

normal force

friction

tension

Which botany phenomenon is primarily based on an understanding of physics

An object whose weight is 100lbf (pound force) experiences a decrease i kinetic energy of 500ft-lb, and an increase in potential energy of 1500ft-lbf.

What are some proxy sites not blocked by lightspeed systems?

The maximum number of orbits in an atom is

A 55.0-kg skydiver free falls for a period of time before opening his parachute. What is his kinetic energy when he reaches a velocity of 16.0 meters/second? 7,040 J 440 J 539 J cannot be determined without knowing his height above the ground

Which of the following is an example of heat transfer through radiation? A. A pot of soup warming on a hot burner. B. A crayon melting on a hot sidewalk. C. Beach sand getting warmed by the sun. D. An egg getting cooked in a pot of boiling water.

Which of the following best describes each particle? A. Protons are negative, neutrons are neutral, and electrons are positive. B. Protons are neutral, neutrons are positive, and electrons are negative. C.

During World War II, both the Allied and Axis powers used propaganda to A. weaken public support for the war. B. downplay public opinion. C. manipulate the public through the use of humor. D. shape public support of the war

What type of simple machine is a hand drill? A) pulley B) wedge C) ramp D) screw

Calculate the wavelength and frequency of the radiation emitted by the electronic transition from the 10th to the 9th excited state of hydrogen.