Which of the following is an example of a physical change?

A. water freezing

B. a cake baking

C. a match burning

D. fireworks exploding

What can you assume has happened if an electron moves to a higher energy level? A) the atom has become more stable B) the electron has lost energy C) the electron has gain energy D) the atom has lost an electron

A centripetal force always causes a centripetal acceleration. True or False

The number of valence shells are responsible for the makeup of the chemical properties of elements. A. True B. False

1. A tennis ball is dropped from a second story window. It is in free fall, accelerating downward at a rate of 9.8 m/s2. At the exact same time, another person throws a tennis ball out the adjacent window with a horizontal velocity of 30 m/s.

If the energy stored in the fully charged battery is used to lift the battery with 100-percent efficiency, what height is attained? Assume that the acceleration due to gravity is 9.8 m/s2m/s2 and is constant with height

The characteristics that follow are characteristics of two of Galileo's surviving double-convex lenses. The numbers given are magnitudes only; you must supply the correct signs. L 1: front radius 950 mm, rear radius 2700 mm, refractive index 1.

Which car has the most kinetic energy? A car of mass 1500 kg with speed 5 m/s or A car of mass 1300 kg with speed 3 m/s or a car of mass 1200 kg with speed 2 m/s or a car mass 1400 kg with speed 4 m/s

A 500 kg table with 4 legs rests on solid flat ground. I place 3 books on the center of the table with masses of 10 kg, 20 kg and 30 kg respectively. What is the normal force between the ground and one leg of the table?

Fluorine-21 has a half-life of approximately 5 seconds. What percentage of the original nuclei would remain after 20 seconds

Which of these is an example of a totalitarian regime A.) Canada under prime minister Trudeau's rule B.) the Soviet Union under Josef lo