Q: Explain why some of the leaves may get detached from a tree if we vigorously shake it branch.

The answer of this cause lies behind the Newton’s First Law of Motion. Initially, leaves and tree both are in rest. But when the tree is shaken vigorously, tree comes in motion while leaves have tendency to be in rest. Thus, because of remaining in the position of rest some of the leaves may get detached from a tree if we vigorously shake its branch.

Question 1

Why is it advised to tie any luggage kept on the roof of a bus with a rope?

Accepted Answer

While the bus is moving, luggage tends to remain in inertia of motion state. When the bus stops, the luggage tends to resist the change and due to inertia of motion it moves forward and may fall off. That's why it is advised to tie any luggage kept on the roof of a bus with a rope.

Question 2

Explain why some of the leaves may get detached from a tree if we vigorously shake it branch.

Accepted Answer

The answer of this cause lies behind the Newton&#8217;s First Law of Motion. Initially, leaves and tree both are in rest. But when the tree is shaken vigorously, tree comes in motion while leaves have tendency to be in rest. Thus, because of remaining in the position of rest some of the leaves may get detached from a tree if we vigorously shake its branch.

Question 3

When a bus suddenly takes a turn, the passengers are thrown outwards because of

Accepted Answer

According to the law of inertia of motion, a body will continue moving with constant velocity unless any force acts on it. When a bus is moving straight the passengers inside are also moving straight but when suddenly bus turn left passengers still continue to move straight  because no force is acting on passengers so they will move with same magnitude and direction i.e. outwards when bus turns .

Question 4

State Newton's first law of motion. Why is it called the law of inertia?

Accepted Answer

Newton's first law of motion: A body continues to be in its state of rest or of uniform motion in a straight line unless an external force is applied to it. It is called the law of inertia because it tells that every material body has a property by virtue of which it resists the change in its state of rest or in its state of motion. This property is called inertia.

Question 5

Explain why,a person travelling in a bus falls forward when the bus stops suddenly.

Accepted Answer

When a bus stops suddenly, its passengers tend to fall forward because due to their inertia the passengers tend to remain in a state of motion even though the bus has come to rest.

Question 6

State Newton's first law of motion and give its one example.

Accepted Answer

First law of motion:Its states that a body at rest will remain at rest and a body in motion will continue in motion in a straight line with uniform speed unless it is compelled by some external force to change its state of rest or of uniform motion.Example:When a bus starts moving all of a sudden, the head of the passenger sitting in the bus strikes the back of his seat. This can be explained on the basis of the first law of motion. The lower part of the body of the passenger remains in contact with the body of the bus, but the upper part is free. When the bus takes a sudden start, the bus comes in motion and so the lower part of the body, but the head and upper part of the passenger&#8217;s body not in contact with the bus, tend to remain at rest and thus, jerked backwards. Similarly, we can explain the jerking of passengers in the forward direction of a bus, when the moving bus stops all of a sudden.

Question 7

A man getting down from a running bus falls forward :

Accepted Answer

Inertia is the tendency of an object to resist any change in their state of motion. When a person alights from the bus, his body would try to continue moving in the direction the bus was moving due to inertia. But as soon as both the feet touches the ground, the lower part of the body comes to  rest while the upper part gets carried away under the effect of inertia resulting into his forward fall.

Question 8

How can Newton's first law of motion be obtained from the second law of motion?

Accepted Answer

To obtain Newton's first law of motion from the second law of motion:From Newton's second law, $F = ma$ If $F = 0$then $ a = 0$This implies that when force is not applied on a body, the acceleration will be zero. If the body is at rest, it will continue to say at rest, when it is moving, it will continue to moves in the same direction will the same speed.Hence, a body not acted upon by an external force does not change its state of rest or motion which is the statement of Newton's first law of motion.

Question 9

State Newton's first low of motion.Give two examples to illustrate Newton's first law of motion.

Accepted Answer

Newton's first law of motion states that a body at rest will remain at rest,and a body in motion will continue in motion in a straight line with a uniform speed unless it is compelled by an external force to change its state of rest or of uniform motion.For example,a book lying on a table remains on the table unless we lift it with the force of our hands.And on a frictionless surface, a moving car continues to be in the state of motion until are applied on it.

Question 10

State and explain the Newton's first law of motion.

Accepted Answer

Newton's First LawNewton's First Law of Motion explains how inertia affects moving and non-moving objects. Newton's first law states that an object will remain at rest or move at a constant speed in a straight line unless it is acted on by an unbalanced force. Inertia comes from mass. Objects with more mass have more inertia.To understand inertia, imagine moving a bowling ball and a golf ball that are at rest. The golf ball has a mass of $0.05 \ kg$, and the bowling ball has a mass of $5 \ kg$. The bowling ball has $100$ times more mass than the golf ball, so it has $100$ times more inertia, too.Now ask yourself, which needs more force to start moving? If you push for the same distance, the bowling ball takes much more force to get it moving the same speed as the golf ball. The bowling ball needs more force because a bowling ball has more inertia than a golf ball. The greater an object's inertia, the greater the force needed to change its motion.According to Newton's first law, an unbalanced force is needed to move the book on your desk. You could supply the force by pushing the book.An unbalanced force is needed to change the speed or direction of the spacecraft. This force could be supplied by the spacecraft's engines.Because of inertia, an object at rest will remain at rest until something causes it to move. Likewise, a moving object continues to move at the same speed and in the same direction unless something acts on it to change its speed or direction.

External Force as Cause of Motion

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Newton's First Law of Motion

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Force as the External Cause of Motion

First Law of Motion