Answer:
F' = F
Explanation:
The gravitational force of attraction between two objects can be given by Newton's Gravitational Law as follows:

where,
F = Force of attraction
G = Universal gravitational costant
m₁ = mass of first object
m₂ = mass of second object
r = distance between objects
Now, if the masses and the distance between them is doubled:

<u>F' = F</u>
Answer:
The mass of the child + skateboard is 50 kg
Explanation:
In this problem, we can apply Newton's second law:
F = ma
where
F is the net force on a system
m is the mass of the system
a is the acceleration of the system
In this problem, our system is the child + the skateboard. The net force on them is
F = 75 N
and their acceleration is

So we can re-arrange the equation above to find their combined mass:

There are many forms of energy, but they can all be put into two categories: kinetic and potential. Kinetic energy is motion––of waves, electrons, atoms, molecules, substances, and objects. Potential energy is stored energy and the energy of position––gravitational energy