Laws of Motion
Short Questions
1. What is motion?
- Motion is the change in position of an object with respect to its surroundings.
2. What is the difference between distance and displacement?
- Distance is the total path traveled; displacement is the shortest path between start and end points.
3. What is speed?
- Speed is the distance traveled per unit of time.
4. What is velocity?
- Velocity is the displacement per unit of time, including direction.
5. What is acceleration?
- Acceleration is the rate of change of velocity.
6. What is uniform motion?
- Uniform motion is when an object covers equal distances in equal time intervals.
7. What is non-uniform motion?
- Non-uniform motion is when an object covers unequal distances in equal time intervals.
8. What does a straight line in a distance-time graph indicate?
- It indicates uniform motion.
9. What is Newton’s first law of motion?
- An object remains at rest or in uniform motion unless acted upon by an unbalanced force.
10. What is inertia?
- Inertia is the tendency of an object to resist changes in its state of motion.
11. What is momentum?
- Momentum is the product of an object’s mass and velocity.
12. What is Newton’s second law of motion?
- The force on an object is equal to its mass times its acceleration (F = ma).
13. What is the unit of force in the SI system?
- The unit of force is Newton (N).
14. What is Newton’s third law of motion?
- Every action has an equal and opposite reaction.
15. What is uniform circular motion?
- It is motion with constant speed along a circular path.
16. What is the formula for speed in uniform circular motion?
- Speed = (2πr) / t, where r is radius and t is time.
17. What is positive acceleration?
- Positive acceleration occurs when velocity increases.
18. What is deceleration?
- Deceleration is negative acceleration, where velocity decreases.
19. What is the law of conservation of momentum?
- Total momentum before and after a collision remains constant if no external force acts.
20. Why does a gun recoil when a bullet is fired?
- The gun moves backward due to the equal and opposite reaction force (Newton’s third law).
Long Questions
1. How can you tell if an object is in motion?
- An object is in motion if its position changes relative to its surroundings. For example, a moving car changes its position compared to a stationary tree.
2. What is the difference between scalar and vector quantities in motion?
- Scalar quantities, like distance and speed, have only magnitude, while vector quantities, like displacement and velocity, have both magnitude and direction. This distinction helps in analyzing motion accurately.
3. How does Newton’s first law explain the behavior of a stationary object?
- Newton’s first law states that a stationary object remains at rest unless an unbalanced force acts on it. For example, a book on a table stays still until someone pushes it.
4. Why is Newton’s first law also called the law of inertia?
- It describes inertia, the property of an object to resist changes in its motion. A heavy object, like a car, needs more force to move due to its greater inertia.
5. How does Newton’s second law relate force, mass, and acceleration?
- Newton’s second law states that force equals mass times acceleration (F = ma). For example, pushing a heavier cart requires more force to achieve the same acceleration as a lighter one.
6. How does Newton’s third law apply to everyday activities like walking?
- When walking, your foot pushes backward on the ground (action), and the ground pushes you forward (reaction). This equal and opposite force pair enables movement.
7. Why does an object in uniform circular motion have acceleration?
- In uniform circular motion, the direction of velocity constantly changes, causing acceleration even if speed is constant. For example, a car turning on a curve accelerates due to changing direction.
8. How can you determine distance traveled using a velocity-time graph?
- The distance traveled is the area under the velocity-time graph. For a uniformly accelerated object, this area represents the total displacement over a time interval.
9. What happens to momentum during a collision according to the law of conservation of momentum?
- In a collision, the total momentum before and after remains the same if no external forces act. For example, in a billiards game, the momentum of the cue ball transfers to the other balls.
10. Why does a high jumper land on a thick bed of sand?
- The sand bed reduces the impact force by increasing the time over which the jumper’s momentum decreases. This application of Newton’s second law helps prevent injuries.
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