What does normal force have to do with gravity?

We found the centripetal acceleration of the earth as it revolves around the sun. compute the centripetal acceleration of a point on the surface of the earth at the equator caused by the rotation of the earth about its axis. (enter the magnitude. the radius of the earth is 6,371 km.)

Amother used 150 watts of power to raise a 15 newton object in a time interval of 8.0 seconds. through what vertical distance was the object raised ?

How does changing the frequency affect the energy of the wave?