In a lightning storm, a large negative charge accumulates in the lower regions of low-lying clouds. Which term best describes this charge? A. electric current B. nuclear force C. electric force D. static electricity​

Light from a sodium lamp passes through a diffraction grating that has 1000 slits per millimeter. the interference pattern is viewed on a screen 1.000 m behind the grating. the first (m = 1) two bright yellow fringes that are visible are 0.7288 m and 0.7300 m from the central maximum. what are the wavelengths of these two fringes?

The velocity of a car traveling in a straight line increases from 0 meters/second to 30meters/second in 8 seconds. what is the average acceleration of the car?

Contrast the force of gravity between these pairs of objects: 1-kg mass and a 2-kg mass that are 1 m apart; a 1-kg mass and a 2-kg mass that are 2 m apart; and two 2=kg masses that are 1 m apart. i dont understand.