Answer:
The rotation of a planet around it's sun
C.) Laser. the light from the laser reflects off the shiny surface as the CD rotates
Answer: Jupiter's mass
Explanation:
From Kepler's third law:

where T is the orbital period of a satellite, a is the average distance of the satellite from the Planet, M is the mass of the planet, G is the gravitational constant.
If the average distance of one of Jupiter's moons to Jupiter and its orbital period around Jupiter is given then mass of the Jupiter can be found:

Explanation:
Power of electric kettle, P = 1 kW
Voltage, V = 220 V
(a) Electric power is given by the formula as follows :

R is resistance

(b) When connected to a 220 V supply, it takes 3 minutes for the water in the kettle to reach boiling point.
Energy supplied is given by :

P is power, 

If it were possible for an object to fall freely near the surface of the Earth,
-- The direction of its velocity would always be "down"; that is, toward the center of the Earth.
-- The size of its velocity would continually increase, at the rate of 9.8 meters per second for every second it falls.