Arocket in orbit just above the atmosphere is moving in uniform circular motion. the radius of the circle in which it moves is 6.381 × 106 m, and its centripetal acceleration is 9.8 m/s2 . what is the speed of the rocket?

The centripetal force for an object moving in circular motion is:

where m is the mass, v the speed of the object and r the radius of the orbit. For Newton's second law, this is equal to

where  is the centripetal acceleration. So we can find the centripetal acceleration by equalizing the two equations:

Since we know the value of the centripetal acceleration of the rocket,  , and the radius of the orbit, , we can solve the previous formula for v, the speed of the rocket:

The correct answer is  "c".  it is "c" because melting is an endothermic change, and endothermic get's energy from surroundings.