Does the number of particles change as the substance changes its state

According to newtons universal law of gravitation, which would change the parh of the ball so it traces out widest curved path possible?

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?

If forces acting on an object are unbalanced. true or false