Answer briefly.
1. Define velocity.
Velocity is the rate of change of displacement. It is the displacement in unit time. It is a vector quantity. The SI unit of velocity is m/s
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2. Distinguish distance and displacement.
| Distance | Displacement |
| Distance is the actual length of the path travelled by a moving body irrespective of the direction. | Displacement is defined as the change in position of a moving body in a particular direction. |
| It is a scalar quantity. | It is a vector quantity. |
| It has magnitude only. | It has both magnitude and direction |
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3. What do you mean by uniform motion?
An object is said to be in uniform motion if it covers equal distances in equal intervals of time how so ever big or small these time intervals may be.
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4. Compare speed and velocity.
| Speed | Velocity |
| Speed is the rate of change of distance or the distance travelled in unit time | Velocity is the rate of change of displacement in unit time. |
| It is a scalar quantity having magnitude only | It is a vector quantity having both magnitude and direction |
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5. What do you understand about negative
acceleration?
When a body moves in a straight line without reversing its direction,
1. If final velocity is less than initial velocity (v <u), the velocity decreases with time and the value of acceleration is negative. It is called negative acceleration.
2. Negative acceleration is called retardation or deceleration.
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6. Is the uniform circular motion accelerated?
Give reasons for your answer.
Yes, uniform circular motion is accelerated.
Reason:
When an object is moving with a constant speed along a circular path, the velocity changes due to the change in direction. Hence, it is an accelerated motion.
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7. What is meant by uniform circular
motion? Give two examples of uniform
circular motion
When an object moves with constant speed along a circular path, the motion is called uniform circular motion.
Example:
1. The Earth moves around the Sun.
2.The Moon moves around the Earth.
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Answer in detail.
1. Derive the equations of motion by
graphical method.
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2. Explain different types of motion
Definition:
Objects which change their position are said to be in motion
Types of motion
1. Linear motion
Motion along a straight line
Example: a person walking on a straight path
2. Circular motion
Motion along a circular path
Example: swirling stone tied to the rope
3. Oscillatory motion
Repetitive to and fro motion of an object at regular interval of time
Example: pendulum
4. Random motion
Motion of the object which does not fall in any of the above categories
5. Uniform motion
An object is said to be in uniform motion if it covers equal distances in equal intervals of time
6. Non uniform motion
An object is said to be in non uniform motion if it covers unequal distance in equal intervals of time
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