Answer:
Mass and height
Explanation:
Gravitational potential energy is energy an object possesses because of its position in a gravitational field. The most common use of gravitational potential energy is for an object near the surface of the Earth where the gravitational acceleration can be assumed to be constant at about 
Which is represented as;

stands for gravitational potantial energy,
m stands for mass of object,
g is the gravitational constant and
h is the height.
Here we see that mass of object and height is directly proportional to the gravitational potential energy.
That means increasing in mass and height will result in increasing gravitational potential energy.
Answer:
8 seconds
Explanation:
power (P) is defined as the rate at which work is done.
power is measured in Watts (W) , when the work done is measured in Joules (J) and time in seconds
by the definition of power,

Go and click to the invitation bar and you can find an option written as " search friends " . Then it's easy to find that unknown user if you're pretty fond with his/her username and DP ( display picture ).
ANSWER IS A)
THE SPEED IS 25 M/S FOR BOTH PEOPLE
Answer:
It's energy will double.
Explanation:
This is because energy, E, is related to frequency, f, by:
E = hf
Where h = Planck's constant
So, double frequency will be 2f
=> E(2f) = 2hf = 2E.
Hence, energy is doubled.