RESONANCE SUMMER VACATION HOMEWORK OF PHYSICS

 

RESONANCE SUMMER VACATION HOMEWORK OF PHYSICS

Q1. Define rest and motion and give two examples of each.

ANS    REST :- An object is said to be at rest if it does not change position with  time is called rest .

EXAMPLE OF REST :-  1. A book sitting on a table

                                        2. A person sitting quietly in a chair

MOTION :- When an object is said to be in motion .if its position change with time is called motion.

EXAMPLE OF MOTION :- 1. A car driving down the road

                                              2. A person running in a park

2. Can a body be at rest and motion at the same time? Explain

ANS   es, a body can be at rest and in motion at the same time, depending on the frame of reference.

 

For example:

 

- A person sitting in a moving train is at rest relative to the train (they're not moving within the train), but they're in motion relative to the ground outside (the train is moving).

 

This shows that rest and motion are relative terms, and it depends on the observer's frame of reference.

es, a body can be at rest and in motion at the same time, depending on the frame of reference.

3. Give three examples to explain that motion is relative.

ANS  1. Train Example: A person sitting in a moving train sees a fellow passenger as being at rest, but an observer standing on the platform sees both passengers as being in motion.

 

2. Car Example: When you're driving in a car, you might feel like you're stationary and the trees outside are moving. But to someone standing near the trees, the car is moving, and the trees are stationary.

 

3. Bus Example: If you're sitting in a bus that's moving alongside another bus, it might feel like your bus is stationary, and the other bus is moving in the opposite direction. But if you look at the road or buildings outside, you'll realize both buses are actually moving.

 

These examples show that motion is relative and depends on the observer's frame of reference!

Q4. Distance as a Vector Quantity

No, distance is a scalar quantity, not a vector quantity. It has only magnitude, not direction.

 

Q5. Vector

A vector is a quantity with both magnitude and direction. Examples include displacement, velocity, and acceleration.

 

Q6. Scalar Quantity

A scalar quantity has only magnitude, no direction. Examples:

 

1. Distance

2. Speed

 

Q7. S.I. Unit of Displacement

The S.I. unit of displacement is meter (m).

 

Q8. Displacement as Zero

When an object returns to its initial position, its displacement can be zero. Example: A car travels from point A to point B and then returns to point A.

 

Q9. Distance and Displacement Equality

No, distance and displacement are not always equal in magnitude. Distance is the total path length, while displacement is the shortest path between initial and final positions.

 

Q10. Runner's Distance and Displacement

If a runner completes a circle, their displacement is zero (since they end up at the starting point), but their distance is the circumference of the circle.

 

Q11. Differences between Distance and Displacement

Here are five differences:

 

1. Distance is a scalar, while displacement is a vector.

2. Distance is always positive, while displacement can be positive, negative, or zero.

3. Distance is the total path length, while displacement is the shortest path.

4. Distance depends on the path taken, while displacement depends only on the initial and final positions.

5. Distance can never be less than displacement.

 

Q12. S.I. Unit of Velocity

The S.I. unit of velocity is meter per second (m/s).

 

Q13. Speed

Speed is the rate of change of distance. It's a scalar quantity.

 

Q14. Velocity

Velocity is the rate of change of displacement. It's a vector quantity.

 

Q15. Uniform Acceleration

A body is said to move with uniform acceleration when its velocity changes by equal amounts in equal time intervals.

 

Q16. S.I. Unit of Speed

The S.I. unit of speed is meter per second (m/s).

 

Q17. Rate of Change of Displacement

The physical quantity corresponding to the rate of change of displacement is velocity.

 

Q18. Vector Quantities

Apart from velocity, two other vector quantities are:

 

1. Displacement

2. Acceleration

 

Q19. Uniform Velocity

A body is said to have uniform velocity when it moves with a constant speed in a straight line.

 

Q20. Uniform Velocity and Speed

If a particle is moving with uniform velocity, it implies:

 

- It's moving with uniform speed (since velocity includes both speed and direction).

- It's moving along a straight line (since uniform velocity implies a constant direction).

 

Q21. Differences between Speed and Velocity

Here are the differences:

 

1. Speed is a scalar, while velocity is a vector.

2. Speed is the rate of change of distance, while velocity is the rate of change of displacement.

3. Speed is always positive, while velocity can be positive, negative, or zero.

 

Q22. Average Speed

To find the average speed:

 

Average speed = Total distance / Total time

= 80 km / 2 hours

= 40 km/h

 

To convert to m/min:

 

40 km/h = 40,000 m / 60 min

= 666.67 m/min

 

To convert to m/s:

 

40 km/h = 40,000 m / 3600 s

= 11.11 m/s

 

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To compare, we need to convert all speeds to the same unit. Let's assume the speeds are:

 

(a) Sanjeev: 12 km/h = 3.33 m/s

(b) Rajeev: 5 m/s (already in m/s)

 

Without the third option, we can't definitively say who has the maximum and least average speed. However, between Sanjeev and Rajeev, Rajeev has a higher average speed.S