Sage-Tips

Do all objects have the same gravitational potential energy?

There is a direct relation between gravitational potential energy and the mass of an object. More massive objects have greater gravitational potential energy. There is also a direct relation between gravitational potential energy and the height of an object.

Does GPE increase as an object falls?

The higher up an object is the greater its gravitational potential energy. The larger the distance something falls through the greater the amount of GPE the object loses as it falls.

What happens to the gravitational potential energy if an object is lifted to a higher place?

Since the gravitational potential energy of an object is directly proportional to its height above the zero position, a doubling of the height will result in a doubling of the gravitational potential energy.

What two factors affect how much gravitational potential energy an object has?

The factors that affect an object’s gravitational potential energy are its height relative to some reference point, its mass, and the strength of the gravitational field it is in.

Does speed affect gravitational potential energy?

When the planet is closest to the Sun, speed v and kinetic energy are the highest, and gravitational potential energy is the lowest. When the planet moves farther away, the speed and kinetic energy decrease, and the gravitational potential energy increases.

What is the acceleration of an object falling in a vacuum?

This object is falling inside a vacuum. According to Newtonian mechanics, F=ma, where F is the force of gravity (no air resistance here), and a is the acceleration, and m is the mass of the object. For gravity, F=mg, where g is the gravitational acceleration, giving a=g. If the object doesn’t hit something first, it will continue to accelerate.

Why do all objects with the same mass fall with same acceleration?

The acceleration of the object equals the gravitational acceleration. The mass, size, and shape of the object are not a factor in describing the motion of the object. So all objects, regardless of size or shape or weight, free fall with the same acceleration. In a vacuum, a beach ball falls at the same rate as an airliner.

What is the relationship between gravitational acceleration and free falling?

The gravitational acceleration g decreases with the square of the distance from the center of the earth. But for many practical problems, we can assume this factor to be a constant. An object that moves because of the action of gravity alone is said to be free falling.

Why is Newton’s 2nd Law of motion only true for gravity?

The secret here is that Newton’s 2nd Law only holds true if gravity is the ONLY force acting on the two objects. If objects fall through the air, then air resistance plays a part. And of course, some objects are more affected by air resistance, like feathers. To design a better experiment, we could try the same objects, but get rid of the air!