1
Newton's Third Law of Motion applies to which of the following situations?
Answer & Solution
Answer: Option
A
Solution:
Let's understand why Option A is the correct answer and what Newton's Third Law of Motion is all about.
Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction. This means whenever one object pushes or pulls another object (the action), the second object pushes or pulls back on the first object with the same strength but in the opposite direction (the reaction). These forces always come in pairs and act on different objects.
Let's look at the options:
Option A: When a person jumps from the boat to the river, the boat goes backwards.
This is a perfect example of Newton's Third Law.
Action: The person pushes the boat backwards with their feet to jump forward.
Reaction: The boat, in turn, pushes the person forward, allowing them to jump. At the same time, because of the force the person applied, the boat moves backwards. The forces are equal in strength and opposite in direction, acting on two different objects (person on boat, boat on person).
Option B: Passengers standing in a bus fall in the back direction, when the stationary bus suddenly moves.
This situation is explained by Newton's First Law of Motion, also known as the Law of Inertia. When the bus suddenly moves forward, the passengers' bodies tend to stay in their original state of rest due to inertia, making them fall backward relative to the bus.
Option C: When a person falls on the cement floor, he gets hurt.
This relates to Newton's Second Law of Motion and the concept of impact. When a person falls on a hard surface like cement, the stopping time (the time it takes for their body to stop moving) is very short. A very short stopping time leads to a very large force being exerted on the person, causing injury. If the stopping time were longer (like falling on a soft mat), the force would be smaller.
Option D: While catching a fast moving cricket ball, a fielder puts his hands backwards.
This is also explained by Newton's Second Law of Motion. By moving his hands backward, the fielder increases the time it takes for the ball to stop. When the time of impact is increased, the average force exerted by the ball on the fielder's hands is reduced, which helps prevent injury.
Therefore, only Option A directly demonstrates the "action-reaction pair" principle of Newton's Third Law.
Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction. This means whenever one object pushes or pulls another object (the action), the second object pushes or pulls back on the first object with the same strength but in the opposite direction (the reaction). These forces always come in pairs and act on different objects.
Let's look at the options:
Option A: When a person jumps from the boat to the river, the boat goes backwards.
This is a perfect example of Newton's Third Law.
Action: The person pushes the boat backwards with their feet to jump forward.
Reaction: The boat, in turn, pushes the person forward, allowing them to jump. At the same time, because of the force the person applied, the boat moves backwards. The forces are equal in strength and opposite in direction, acting on two different objects (person on boat, boat on person).
Option B: Passengers standing in a bus fall in the back direction, when the stationary bus suddenly moves.
This situation is explained by Newton's First Law of Motion, also known as the Law of Inertia. When the bus suddenly moves forward, the passengers' bodies tend to stay in their original state of rest due to inertia, making them fall backward relative to the bus.
Option C: When a person falls on the cement floor, he gets hurt.
This relates to Newton's Second Law of Motion and the concept of impact. When a person falls on a hard surface like cement, the stopping time (the time it takes for their body to stop moving) is very short. A very short stopping time leads to a very large force being exerted on the person, causing injury. If the stopping time were longer (like falling on a soft mat), the force would be smaller.
Option D: While catching a fast moving cricket ball, a fielder puts his hands backwards.
This is also explained by Newton's Second Law of Motion. By moving his hands backward, the fielder increases the time it takes for the ball to stop. When the time of impact is increased, the average force exerted by the ball on the fielder's hands is reduced, which helps prevent injury.
Therefore, only Option A directly demonstrates the "action-reaction pair" principle of Newton's Third Law.