4. what does doubling the voltage do to the strength of the electromagnet?

Aplane flies directly between two cities, a and b, which are separated by . from a to b, the plane flies into a headwind. on the return trip from b to a, the wind velocity is unchanged. the trip from b to a takes less than the trip from a to b. what is the airspeed of the plane, assuming it is the same in both directions

If a simple machine reduces the strength of a force, what must be increased?

The force it would take to accelerate an 900-kg car at the rate of 6m/s2