Why are large astronomical bodies such as planets and stars

Orque can be calculated by multiplying the force (n) applied at 90? to the lever arm at a distance (m) from the pivot point (point of rotation), the compound si unit for the torque is n? m. if the force (at 90? to the lever arm) applied is 15 n and it is applied at 2.0 m from the pivot point (point of rotation), what is the torque on the lever?

A100-watt light bulb illuminates a solar cell. the electricity from the solar cell operates a water pump that delivers 1 watt of power. what is the efficiency of the system?

What are the north and south poles of a solenoid change with?