Well, I'll try to write the formula in a way that's not confusing, but I'm afraid it might be slightly confusing anyway.
When you're working with dB, the basic rule is
A change of 10 dB means either multiplying or dividing by 10 .
Multiply something by 10 ==> it increases by 10 dB. Divide something by 10 ==> it decreases by 10 dB.
It turns out that another way to write all of this is . . .
An increase of 10 dB ===> multiply the original amount by 10¹ An increase of 20 dB ===> multiply the original amount by 10² An increase of, say, 7 dB ===> multiply the original amount by 10⁰·⁷
A decrease of 10 dB ===> multiply the original amount by 10⁻¹ A decrease of 30 dB ===> multiply the original amount by 10⁻³ A decrease of, say, 13 dB ===> multiply the original amount by 10⁻¹·³
This question says: The sound increases by 5 dB .
That means the original 'intensity' or 'power' of the sound is multiplied by 10⁰·⁵ = √10 = about 3.162 (rounded) .
F=mg=Gm1m2/r^2 g=Gm2/r^2 g=2Gm2/(2r)^2=2Gm2/4r^2=Gm2/2r^2 So since there is half times the gravity on this unknown planet that has twice earth's mass and twice it's radius, then the person can jump twice as high. 1.5*2= 3m high
