Well we have two concepts of gravity now. In Newton's concept masses create forces between them. In Einstein's concept mass distorts time and space around it and makes masses move as if there are forces between them.
So whichever concept you prefer it's the presence of mass that creates gravity.
Answer:
electric energy ( power ) = 300000 W
Explanation:
given data
mechanical (hydroelectric) energy = 120 MJ/min = 2000000 J/s
efficiency = 15 % = 0.15
solution
we know that Efficiency of electric engine is expression as
Efficiency = Mechanical energy ÷ electric energy ......................1
and here dam electrical power output is
put here value in equation 1
electric energy ( power ) = Efficiency × Mechanical energy ( power )
electric energy ( power ) = 0.15 × 2000000 J/s
electric energy ( power ) = 300000 W
B. Strong nuclear
Because the strong nuclear force is the strongest at short distances, it dominates over the other forces and the two protons become bound, forming a helium nucleus (typically a neutron is also needed to keep the helium nucleus stable).
The density of an object is given by:
D = M/V
D = density, M = mass, V = volume
The volume of the cube V is given by:
V = s³
where s = side length
Make a substitution:
D = M/s³
Given values:
M = 20kg, s = 20×10⁻²m
Plug in and solve for D:
D = 20/(20×10⁻²)³
D = 2500kg/m³
