Sir Isaac Newton and the Falling Apple

Question

Isaac Newton was a scientist and mathematician who lived in England in the 1600s-1700s. Sometimes, cartoons will depict Isaac Newton as a scientist who was hit in the head by a falling apple and "discovered" gravity. That's not entirely accurate, but there is a bit of truth to the legend. When Newton was a young man, he spent time living away at a school called the University of Cambridge. However, when the bubonic plague caused an epidemic in 1665, the school was temporarily closed, and Newton and his classmates were sent home. While he was at home, he was on property near his family's house when he noticed an apple that was falling from a tree. He wondered why apples always fall straight to the ground instead of falling sideways or even falling upward. When school reopened, he went back and continued his studies. He kept thinking about the falling apple and its straight-down path. As he studied more and more, he eventually developed the ideas that became known as the law of universal gravitation and helped scientists, inventors, and ordinary people to understand motion. Years later, he told the story of the falling apple to a man named William Stuckeley, who later published the story in a biography he wrote about Newton. Interestingly, the same apple tree is still growing on the same property in England, over 350 years later.
Question 1
Even though modern scientists have developed new ideas that go beyond Newton's ideas, we still know that gravity causes falling objects to appear to fall straight toward the Earth.

The image below shows the positions of a falling ball that was dropped from 10 meters high.

a. At which position is the potential energy the greatest?

(1 point)
Responses

10 m
10 m

8 m
8 m

5 m
5 m

0 m
0 m
Question 2
b. At what position is the kinetic energy the greatest?(1 point)
Responses

10 m
10 m

just below 10 m
just below 10 m

just above 0 m
just above 0 m

0 m
0 m
Question 3
c. What is happening to potential energy as the ball is falling?(1 point)
Responses

Potential energy is decreasing.
Potential energy is decreasing.

Potential energy is increasing.
Potential energy is increasing.

Potential energy is staying the same.
Potential energy is staying the same.

It is impossible to tell.
It is impossible to tell.
Question 4
d. What is happening to kinetic energy as the ball is falling?(1 point)
Responses

Kinetic energy is decreasing.
Kinetic energy is decreasing.

Kinetic energy is increasing.
Kinetic energy is increasing.

Kinetic energy is staying the same.
Kinetic energy is staying the same.

It is impossible to tell.
It is impossible to tell.
Question 5
e. What is happening to total energy as the ball is falling?(1 point)
Responses

Total energy is decreasing.
Total energy is decreasing.

Total energy is increasing.
Total energy is increasing.

Total energy is staying the same.
Total energy is staying the same.

It is impossible to tell.

Answer 1

Here are the answers to your questions regarding energy changes as a ball falls from a height:

Question 1 a. At which position is the potential energy the greatest?

• Answer: 10 m

Question 2 b. At what position is the kinetic energy the greatest?

• Answer: just above 0 m

Question 3 c. What is happening to potential energy as the ball is falling?

• Answer: Potential energy is decreasing.

Question 4 d. What is happening to kinetic energy as the ball is falling?

• Answer: Kinetic energy is increasing.

Question 5 e. What is happening to total energy as the ball is falling?

• Answer: Total energy is staying the same.

In summary, as the ball falls, its potential energy decreases while its kinetic energy increases, but the total energy remains constant (assuming no air resistance or other forms of energy loss).