<span>Submarines are equipped with water tanks called ballast tanks that fill up to submerge the vessel. Emptying the tanks and filling them with air causes the submarine to surface.</span>
The gravitational potential energy U is defined as the product of mass m, the acceleration of gravity g and the height of object h.

We do not have the mass of the hiker. But we know that its W weight is:

Where

So:
.
So:

J
The hiker has gained 30,000 J of energy
newton 1st law: w no external force, a body will stay at rest or in constant uniform motion.
a motor raises the car up the tower. cuz it moves w/ constant vel, there is no external force: the motor force is the same n in opposity direction as the gravity force on car.
Answer:
I am happy with you the father said to his daughter
Answer:
The inner planets are closer to the Sun and are smaller and rockier. The outer planets are further away, larger and made up mostly of gas. The inner planets (in order of distance from the sun, closest to furthest) are Mercury, Venus , Earth and Mars.
Explanation: