Select the correct answer 1. Instruments that produce sound are called sources of light.

2. Music has no ability to heal the mental stress.

3. A medium is necessary for sound travel.

4. We hear sounds of frequencies below 20 Hz. O First answer O Second answer O Third answer O Forth answer

What color would an object that reflects green and blue light appear to be in white light? a. blue b. cyan c. magenta d. black

Compare the patterns of the two waves shown in the image. which statement is true about these waves?

A980-kg sports car collides into the rear end of a 2300-kg suv stopped at a red light. the bumpers lock, the brakes are locked, and the two cars skid forward 2.6m before stopping.the police officer, estimating the coefficient of kinetic friction between tires and road to be 0.80, calculates the speed of the sports car at impact. what was that speed?