Which wave interaction is responsible for echoes? O A. Diffraction
B. Interference
C. Reflection
D. Refraction

The radius of a sphere is increasing at a rate of 9 cm/ sec. find the radius of the sphere when the volume and the radius of the sphere are increasing at the same numerical rate.

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.

Atorque acting on an object tends to produce a. equilibrium b. rotation c. linear motion d. velocity e. a center of gravity