How long is the racetrack if it takes a racecar 3.4 s travelling at 75 m/s to finish?

May someone explain how to do this question?

Hydrogen atoms are excited by a laser to the =4n=4 state and then allowed to emit. what is the maximum number of distinct emission spectral lines (lines of different wavelengths) that can be observed from this system? 8 6 2 7 4 5 1 3 calculate the wavelength of the 4⟶14⟶1 transition. =λ=

Abowling ball rolling down the lane toward the pins has gravitational potential energy. a. no b. a lot of c. a little