Answer:
The gravitational force is definitely acting downwards towards the ground and this is equal to the weight of the skydiver.
the acceleration a = 7.8 m/s²
Explanation:
Given that :
the mass of the skydiver = 60 kg
Velocity = 50 m/s
Thus; gravitational force is definitely acting downwards towards the ground and this is equal to the weight of the skydiver.
Also; the air resistance is acting upward and the resultant of both forces = mass×acceleration
So;
mg-R = ma
60(9.8) - 120 = 60(a)
588 -120 = 60a
468 = 60a
a = 
a = 7.8 m/s²
Hence, the acceleration a = 7.8 m/s²
The expression commonly used for potential gravitational energy is just simplification. It is actually just the first term in Taylor expansion of the real expression.
In general, the potential energy of gravitational field is defined as:

Where G is universal gravitational constant, and r is the distance between the objects centers of mass. Negative sign represents the bound state.
Since we are not given the mass of the planet we have to calculate it.

This formula can be used for any planet. It gives you the gravitational acceleration on the planet's surface. We can use it to calculate the planet's mass:

Now we can calculate the potential energy of that cannonball when it reaches its maximum height.

When we plug in the numbers we get:

The potential energy has to be equal to the kinetic energy.
The force per unit of length between two wires carrying current is

where I1 and I2 are the currents in the two wires, while r is the distance between them.
We can see from the formula that the force is proportional to the product between I1 and I2:

so, if we double both I1 and I2, we get a factor 4:

so, the force between the wires will be 4 times the original value.