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Q1. What is the total length of the actual path traveled by an object?
Distance is the complete length of the actual path an object takes from start to finish. It doesn’t matter which direction the object moves; we simply add up all the meters or kilometers it covered. For example, if you walk 2 km to school and 2 km back home, the total distance you traveled is 4 km. It is a scalar quantity, meaning it only has magnitude.
Q2. Which quantity has both magnitude and direction?
A quantity that has both magnitude (size or amount) and direction is called a vector quantity. Displacement is a vector because it tells you not only how far you are from the starting point but also in which direction. For example, saying “100 meters towards the North” describes displacement, whereas distance would just say “100 meters” without direction.
Q3. The SI unit of distance and displacement is ______.
The International System of Units (SI) uses the metre (m) as the standard unit for measuring length. This applies to both distance and displacement. Kilometres and centimetres are also units of length but are not the official SI unit. The metre is used in all scientific measurements worldwide.
Q4. A body moves in a circle and returns to its starting point. What is its displacement?
Displacement is the shortest straight-line distance between the starting point and the ending point. Since the body returns to its exact starting point after completing the circle, the initial and final positions are the same. The shortest distance between two identical points is always zero, regardless of how long the path traveled was.
Q5. Which of the following can never be negative?
Distance is a scalar quantity, which means it only has magnitude or size. You cannot have a negative length of a path. It is always zero or a positive number. Displacement, velocity, and acceleration can all be negative because they indicate direction, such as moving backward or slowing down.
Q6. What is the term for the distance traveled by an object per unit of time?
Speed is the rate at which an object covers distance. It is calculated by dividing the total distance traveled by the total time taken. For example, if you run 100 metres in 10 seconds, your speed is 10 m/s. Speed only tells you how fast something is moving, not in which direction.
Q7. What is the SI unit of speed and velocity?
Speed and velocity both measure how fast an object’s position changes. The SI unit for both is “metres per second”, written as m/s. While km/h is commonly used in everyday life, the standard scientific unit is m/s. Note that m/s² is the unit for acceleration, not speed or velocity.
Q8. Speed in a given direction is called ______.
Velocity is the vector version of speed. It tells us both the speed of an object and the direction in which it is moving. For example, saying “a car is moving at 50 km/h” is describing speed, but saying “a car is moving at 50 km/h towards the north” is describing its velocity.
Q9. A car travels 60 km in the first hour and 80 km in the second hour. What is its average speed?
Average speed is calculated by dividing the total distance traveled by the total time taken. The total distance is 60 km + 80 km = 140 km. The total time is 1 hour + 1 hour = 2 hours. So the average speed is 140 km ÷ 2 h = 70 km/h.
Q10. When is the magnitude of average velocity equal to the average speed?
Average speed depends on the total path length, while average velocity depends on displacement. These two will only be equal if the distance and displacement are the same. This happens when the object moves in a single, straight line without turning around or changing direction.
Q11. What type of motion is it when an object covers equal distances in equal intervals of time?
“Uniform” means “constant” or “unchanging.” If an object covers the same distance every second (or any fixed time interval), we say it is moving with uniform motion. An example would be a train moving on a straight track without changing its speed.
Q12. Which graph for uniform motion is a straight line inclined to the time axis?
For uniform motion, the speed is constant, so the distance increases steadily over time. When you plot this on a graph with distance on the y-axis and time on the x-axis, the result is a straight, slanted line. The slope of this line gives the speed.
Q13. In non-uniform motion, the speed of the object ______.
“Non-uniform” means “not constant.” In non-uniform motion, the speed of the object is not fixed and can increase, decrease, or change in any way over time. Most real-life motions, like a car moving in city traffic, are non-uniform.
Q14. Which device in vehicles measures the distance traveled?
An odometer is an instrument found on a vehicle’s dashboard that counts and records the total distance the vehicle has traveled, usually in kilometres or miles. A speedometer, on the other hand, measures the instantaneous speed of the vehicle.
Q15. What is the rate of change of velocity called?
Acceleration tells you how quickly an object’s velocity is changing. This change could be an increase in speed (positive acceleration), a decrease in speed (negative acceleration or retardation), or a change in direction. It is a vector quantity.
Q16. What is the SI unit of acceleration?
Acceleration is the change in velocity (measured in m/s) divided by the time taken (measured in seconds). So the unit becomes (m/s) ÷ s, which simplifies to metres per second squared (m/s²).
Q17. A car increases its speed from 20 m/s to 30 m/s in 5 seconds. What is its acceleration?
Acceleration is calculated as change in velocity divided by time. The change in velocity is final velocity minus initial velocity, which is 30 m/s – 20 m/s = 10 m/s. Dividing this by the time taken of 5 seconds gives 10 ÷ 5 = 2 m/s².
Q18. Negative acceleration is also known as ______.
When an object slows down, its acceleration is in the opposite direction to its motion. This negative acceleration is commonly called retardation or deceleration. For example, when a driver applies brakes, the car experiences retardation.
Q19. When an object moves with uniform velocity, its acceleration is ______.
Uniform velocity means the object is moving at a constant speed in a straight line without changing direction. Since both speed and direction are not changing, the velocity is constant. Therefore, the rate of change of velocity, which is acceleration, is zero.
Q20. Which of the following is the correct equation of motion?
This is the first equation of motion, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time. It relates how velocity changes under uniform acceleration. The other options have incorrect formulas.
Q21. What does the slope of a distance-time graph represent?
The slope of a distance-time graph is calculated as the change in distance divided by the change in time, which is exactly the definition of speed. A steeper slope means higher speed, while a flat horizontal line means the object is at rest.
Q22. In a velocity-time graph, what does the area under the curve represent?
The area under a velocity-time graph gives the displacement of the object. This is because displacement equals velocity multiplied by time. For example, if you have a rectangle with height equal to velocity and width equal to time, its area gives the distance covered.
Q23. What is the shape of a speed-time graph for an object moving with constant acceleration?
When acceleration is constant, the speed increases uniformly with time. This means the graph of speed versus time is a straight line that slopes upward. The slope of this line is equal to the acceleration.
Q24. What does a horizontal line on a velocity-time graph indicate?
A horizontal line on a velocity-time graph means the velocity is not changing over time. Since acceleration is the rate of change of velocity, if velocity is constant, the acceleration is zero. This indicates uniform motion.
Q25. When a body moves in a circular path with constant speed, its motion is called ______.
When an object moves along a circular path at a constant speed, it is said to be in uniform circular motion. Although the speed is constant, the direction of motion is continuously changing, so the velocity is not constant.
Q26. Is the velocity constant in uniform circular motion?
In uniform circular motion, the speed (magnitude of velocity) remains constant, but the direction of motion keeps changing as the object moves around the circle. Since velocity is a vector quantity that includes both speed and direction, the velocity is not constant.
Q27. What is the direction of acceleration in uniform circular motion?
In uniform circular motion, even though the speed is constant, the direction keeps changing. This change in direction requires an acceleration that always points towards the centre of the circle. This is called centripetal acceleration, meaning “centre-seeking.”
Q28. Which equation of motion connects initial velocity, acceleration, displacement, and final velocity?
This is the third equation of motion. It is very useful because it relates the final velocity (v), initial velocity (u), acceleration (a), and displacement (s) without needing the time. It helps when time is not given in the problem.
Q29. To find the distance covered in the nth second of motion, which equation is used?
This is the formula for the distance traveled during the nth second. It tells you how much distance is covered in that specific second (between t = n-1 and t = n). It is derived from the difference between the distance covered in n seconds and in (n-1) seconds.
Q30. A body starts from rest (u=0) with acceleration ‘a’. What is its velocity after time ‘t’?
The first equation of motion is v = u + at. Since the body starts from rest, the initial velocity u is zero. Substituting u = 0 gives v = 0 + at, which simplifies to v = at. So the velocity is simply acceleration multiplied by time.
Q31. What type of quantity is distance?
A scalar quantity is one that has only magnitude (size or amount) and no direction. Distance is a scalar because it just tells you how much ground an object has covered, without any information about the direction of travel.
Q32. What type of quantity is velocity?
A vector quantity is one that has both magnitude and direction. Velocity is a vector because it describes not only how fast an object is moving but also the direction in which it is moving. This makes it different from speed, which is scalar.
Q33. Which of these is a scalar quantity?
Speed is a scalar quantity because it only tells you how fast an object is moving without giving any direction. Displacement, velocity, and acceleration are all vector quantities because they include both magnitude and direction.
Q34. 1 km/h is equal to ______ m/s.
To convert km/h to m/s, we multiply by 1000 (to convert kilometres to metres) and divide by 3600 (to convert hours to seconds). So 1 km/h = 1000/3600 = 5/18 m/s. This is a useful conversion to remember for solving numerical problems.
Q35. A state of rest is considered a state of ______.
When an object is at rest, it is not moving, which means its position is not changing with time. Therefore, its velocity is zero. It is important to understand that rest and motion are relative; an object at rest has zero velocity relative to a particular observer.
Q36. If the displacement-time graph of an object is parallel to the time axis, the object is ______.
A displacement-time graph shows how displacement changes with time. If the line is parallel to the time axis (horizontal), it means the displacement is not changing over time. The object is staying at the same position, which means it is at rest.
Q37. A particle is moving with a uniform speed. Is its acceleration necessarily zero?
Acceleration is the rate of change of velocity, not just speed. If an object moves with uniform speed in a straight line, its velocity is constant and acceleration is zero. But if it moves with uniform speed in a circular path, its direction changes continuously, so velocity changes and acceleration is not zero.
Q38. A freely falling body is an example of ______.
A freely falling body falls under the influence of gravity, which causes it to accelerate. Its speed increases continuously as it falls, so it is not covering equal distances in equal intervals of time. Therefore, its motion is non-uniform.
Q39. The distance traveled by a moving body is directly proportional to time. What is the nature of its motion?
If distance is directly proportional to time, it means that as time increases, distance increases at a constant rate. This means the object is covering equal distances in equal intervals of time, which is the definition of uniform motion.
Q40. A speedometer measures ______.
A speedometer is an instrument in a vehicle that shows the speed of the vehicle at any particular moment. This is called the instantaneous speed. It does not measure average speed over a journey or the total distance traveled (that is done by an odometer).
Q41. A body is said to be in motion if its position changes with respect to a ______.
Motion is always relative. A body is said to be in motion if its position changes with respect to a fixed point or a reference point. For example, a person sitting in a moving train is at rest relative to the train but in motion relative to the ground.
Q42. What is the formula for average velocity?
Average velocity is defined as the total displacement divided by the total time taken. This is different from average speed, which uses total distance. Displacement is the straight-line distance from start to finish, so average velocity gives the rate of change of position.
Q43. If a body moves with constant acceleration, which of the following is true?
Constant acceleration means that the velocity of the body changes by the same amount in every equal interval of time. This is the definition of uniform acceleration. The velocity changes uniformly, while speed may or may not change uniformly if direction also changes.
Q44. In a distance-time graph, a steeper slope indicates ______.
The slope of a distance-time graph represents speed. A steeper slope means that the distance is increasing more rapidly with time, which indicates a higher speed. A gentle slope means slower speed, and a horizontal line means the object is at rest.
Q45. What does a negative slope on a velocity-time graph indicate?
A negative slope on a velocity-time graph means that velocity is decreasing over time. This indicates negative acceleration, which is also called deceleration or retardation. The object is slowing down.
Q46. A boy runs 100 m in 20 s. What is his speed?
Speed is calculated as distance divided by time. Here, distance is 100 metres and time is 20 seconds. So speed = 100 ÷ 20 = 5 m/s. This means the boy covers 5 metres every second.
Q47. A train moving with a velocity of 30 m/s comes to rest in 10 seconds. What is its acceleration?
Acceleration is change in velocity divided by time. The final velocity is 0 m/s (since it comes to rest) and the initial velocity is 30 m/s. Change in velocity = 0 – 30 = -30 m/s. Dividing by time (10 s) gives -30 ÷ 10 = -3 m/s². The negative sign indicates deceleration.
Q48. What remains constant in uniform circular motion?
In uniform circular motion, the object moves along a circular path with a constant speed. However, its velocity is not constant because the direction keeps changing. Similarly, acceleration is also not constant in direction, and displacement keeps changing.
Q49. Which law of motion defines the concept of force?
Newton’s Second Law of motion gives a mathematical definition of force. It states that force is equal to the rate of change of momentum, or F = ma (force equals mass times acceleration). While the First Law describes what force does (changes state of motion), the Second Law defines it quantitatively.
Q50. The motion of a pendulum is an example of ______.
A pendulum swings back and forth in a regular, repeating pattern. This type of motion that repeats itself after fixed intervals of time is called periodic or oscillatory motion. It is not rectilinear (straight line) because it moves along an arc, and it is not circular because it does not complete full circles.