What hits the atmosphere faster than 90,000 miles per hour
a.) comets
b.)meteors
c.)meteoroids

According to social exchange theory, altruistic behaviors benefit the individual who performs them.

The 10-kg double wheel with radius of gyration of 125mm about o is connected to the spring of stiffness k = 600 n/m by a cord which is wrapped securely around the inner hub. if the wheel is released from rest on the incline with the spring stretched 225 mm, calculate the maximum velocity v of its center o during the ensuing motion. the wheel rolls without slipping

The movement of electrons between atoms is called an