What is the difference between the control group and the experimental group in an experimental study?

Arescue plane flying horizontally at spots a survivor in the ocean directly below and releases an emergency kit with a parachute. because of the shape of the parachute, it experiences insignificant horizontal air resistance. if the kit descends with a constant vertical acceleration of, how far away from the survivor will it hit the waves?

Modern physics a photon emitted from an excited hydrogen atom has an energy of 3.02 electron volts. which electron energy-level transition would produce this photon? a. n=1 to n=6 b. n=2 to n=6 c. n=6 to n=1 d. n=6 to n=2 i chose b but the correct answer is d can someone tell me why? and what's the difference?

The strong nuclear force acts over a small distance than the electrostatic force. true or false