What’s the velocity of a ball falling with 100 joules of kinetic energy and a mass of 2 kilograms?

3 m/s
5 m/s
7 m/s
8 m/s
10 m/s

What would the difference of spectral lines emitted by hydrogen gas in distant galaxies which is normally found at a wavelength of 21 cm on earth, be observed at 21.1 centimeters?

What color of light must blue light mix with to create white light? a. yellow b. white c. blue d. green

The magnetic field inside a superconducting solenoid is 4.50 t. the solenoid has an inner diameter of 6.20 cm and a length of 26.0 cm. determine (a) the magnetic energy density in the field and (b) the energy stored in the magnetic field within the solenoid.