By definition, power is the amount of energy consumed (or produced) in a second. (or more precisely, it is the rate of change in energy).
so anything which uses energy in a known time period can be labeled with a power rating.
an example for power could be a nuclear plant; traditional nuclear plants produce somewhat close to 1 giga watts (which means 1 giga joules in a second)
Acceleration = velocity / time.
You first find the mass and the volume of that object. Then you divide mass ÷ volume
Same size as object should be the answer, it is a “plane” mirror