What is necessary to accelerate a 70-kg object at a rate of 4.2m/s2?

If a ball is dropped from rest from an elevated position at the same instant that a second ball is launched horizontally (from the same height), then which ball will hit the ground first? Assume the balls behave as projectiles

Does sound increases when it's cold

If cast iron is such a hard metal why dont the military use cast iron to armor their tanks? Is it cuz cast iron is such a heavy metal that itll make the tank slow? Or is there not enough of cast iron on earth?

What three things use energy transferred by electricity?

A water wave has a frequency of 2 HZ and a wavelength of 5 meters what is its speed

What does a hurricane hunter do

Why is fluorine special in terms of electronegativity?

The airbag inflates and deflates quickly so

Two conducting spheres are each given a charge Q. The radius of the larger sphere is three times greater than that of the smaller sphere.

A solenoid with a ferromagnetic core is