Which statement is true? a. some molecules may contain no atoms. b. some elements found in nature exist as molecules. c. some compounds include only one type of element. d. some atoms are made of two or more different elements.

Acompound machine is also called a machine. a. force b. simple c. complex d. directional

Students design a model roller-coaster track. they place a rubber ball at the highest point on the track and let it go. the ball rolls along the track pulled only by the force of gravity. eventually, it comes to a stop. which change to the design will result in the ball moving the greatest distance?

The charge on an electron is 1.60218 × 10−19 c and its mass is 9.10939 × 10−31 kg. how strong a magnetic field must be experienced by the electron if its path is a circle of radius 5.5 cm? answer in units of t.