Question

1. Define the terms rest and motion? Give one example for
each.
2. Can an object be at rest as well as in motion at same
time?
3. Name the quantities which need both magnitude and
direction for their complete description.
4. Differentiate between distance and displacement.
5. Can the displacement be greater than the distance
travelled by an object? Explain.
6. Write short notes on uniform and non-uniform motion.
7. Define uniform and non-uniform speed.
8. Can the average speed of a moving body ever be zero?
9. What is a speedometer used for?
10.What is an Odometer used for?

Answer 1

Answer:

Ans 1. Rest and Motion are opposite terms. When we say rest, we mean that the object has not movement or it's speed is zero. When we say motion, we mean that the object is moving and it's speed is above zero.

Ans 2. No, an object can't be at rest and motion at the same time. It can be either at rest or at motion.

Ans 3. Not sure

Ans 4. (i) Distance is a scalar quantity but Displacement is a vector quantity

(ii)  Distance is how much ground an object has covered while displacement is how far out of place an object is

(iii) Distance can be measured along an irregular path but displacement can be measured only across a straight line.

Ans 5. No, it can't be greater. It can only be equal to or lesser than the distance

Ans 6. Uniform Motion is when the speed of the object is constant, and non-uniform motion is when the speed of the object is not constant.

Ans 7. Same as 6

Ans 8. No

Ans 9. Speedometer is used to measure the speed of an object.

Ans 10. Odometer is used to measure distance covered by an object.

Explanation:

Answer 2

$\huge\sf\fbox\red{Answer : - 1}$

✯ Rest :-

A body is said to be at rest if it does not change its position with respect to its immediate surroundings.

Example :- (1) A book lying on the table will not change its position if it is not disturbed. So, it is in a state of rest.

(2) A bench in a park fixed under a tree is at rest as there is no change in its position.

✯Motion :-

A body is said to be in motion if it changes its position with respect to its immediate surrounding.

Example :- (1) When a moving car changes its position with respect to a tree or a lamp post by the side of the road, the car is said to be in motion.

(2) A flying bird is also said to be in motion as it changes its position with respect to stationary objects such as trees.

$\huge\sf\fbox\red{Answer : - 2}$

Yes, an object can be at rest with respct to one object andcan bein motion with respect to one object and can be in motion with respect to another object. Example - A body lying on earth is at rest w. r. t. earth but the same body is in motion with respect to another planet because earth and the placet are in relative motion. Thus rest and motion are relative terms.

$\huge\sf\fbox\red{Answer : - 3}$

A quantity which needs both magnitude and direction for their complete description is called vector quantities.

$\huge\sf\fbox\purple{Answer :- 4}$

✯ Distance :-

1. Definition :- The complete length of the path between any two points is called distance.
2. Denotation :- d
3. Quantity :- Distance is a scalar quantity as it only depends upon the magnitude and not the direction .
4. Formula :- Speed × Time
5. Possible Values :- The distance can only have positive values .
6. Measurement :- The distance can be measured along a non-straight path.
7. Path Dependence :- Distance depends upon the path i.e. it changes according to the path taken.

✯ Displacement :-

1. Definition :- Displacement is the direct length between any two points when measured along the minimum path between them.
2. Denotation :- s
3. Quantity :- Displacement is a vector quantity as it depends upon both magnitude and direction .
4. Formula :- Velocity × Time
5. Possible Values :- Displacement can be positive, negative, and even zero.
6. Measurement :- Displacement can only be measured along a straight path.
7. Path Dependence :- Displacement does not depend upon the path and it only depends upon the initial and final position of the body.

$\huge\sf\fbox\purple{Answer : - 5}$

Displacement can never be greater than the distance travelled by an object. Although, it can be equal to distance.

Distance is the total path traversed by a body. Its is scalar quantity. The direction of motion is not considered. All the turns are going to be added to the value.

Displacement the shortest distance between initial position of the body and its final position. The magnitude is obtained by measuring the length of the straight line joining the two positions. Hence, the displacement is going to be always less than distance travelled by the body, except one case.

The only case in which displacement is equal to distance is when the body moves in one direction in a straight line.

$\huge\sf\fbox\purple{Answer : - 6}$

✯ Uniform Motion

Definition: This type of motion is defined as the motion of an object in which the object travels in a straight line and its velocity remains constant along that line as it covers equal distances in equal intervals of time, irrespective of the duration of the time. Example :-

1. If the speed of a car is 10 m/s, it means that the car covers 10 meters in one second. The speed is constant in every second.
2. Movement of blades of a ceiling fan.

✯ Non Uniform Motion

Definition : This type of motion is defined as the motion of an object in which the object travels with varied speed and it does not cover same distance in equal time intervals, irrespective of the time interval duration. Example :-

1. If a car covers 10 meters in first two seconds, and 15 meters in next two seconds.
2. The motion of a train.

$\huge\sf\fbox\purple{Answer : - 7}$

When an object travells equal distance in equal interval of time then it is said to be travelling with uniform speed whereas if an object travells unequal distances in equal interval of time then it is said to be travelling with non-uniform speed.

$\huge\sf\fbox\purple{Answer : - 8}$

The average velocity of a moving object can be zero in the case of a circular path as displacement will be zero but average speed cannot be zero for a moving object.

$\huge\sf\fbox\purple{Answer : - 9}$

A speedometer is a device used to measure the traveling speed of a vehicle, usually for the purpose of maintaining a sensible pace.

$\huge\sf\fbox\purple{Answer : - 10}$

An odometer is a device that is used for measuring the distance traveled by a vehicle. The odometer is usually situated in the vehicle's dashboard. The word "odometer" is derived from two Greek words meaning path and measure.