Kinematics – One Word Answers (With Explanation)
1. Q: What do we call a quantity having only magnitude?
A: Scalar
Explanation: Scalars are quantities described completely by magnitude only (e.g. distance, speed, time, mass).
2. Q: What do we call a quantity having both magnitude and direction?
A: Vector
Explanation: Vectors require both magnitude and direction to describe them fully (e.g. velocity, acceleration).
3. Q: What is the shortest distance between the initial and final positions of an object?
A: Displacement
Explanation: It’s a vector quantity that shows the direct path between start and end points.
4. Q: What is the total length of the path travelled by a body?
A: Distance
Explanation: It is a scalar quantity and always positive.
5. Q: What is the rate of change of displacement called?
A: Velocity
Explanation: Velocity = displacement/time; it can be positive, negative, or zero.
6. Q: What is the rate of change of distance called?
A: Speed
Explanation: Speed = distance/time; it is always positive.
7. Q: When velocity remains constant with time, what is the motion called?
A: Uniform Velocity
Explanation: Both magnitude and direction remain unchanged.
8. Q: What is the rate of change of velocity called?
A: Acceleration
Explanation: Acceleration = change in velocity/time; it is a vector.
9. Q: What is motion with constant acceleration known as?
A: Uniformly Accelerated Motion
Explanation: Acceleration remains the same throughout (e.g. free fall).
10. Q: What is the acceleration due to gravity on Earth called?
A: g
Explanation: It’s approximately 9.8 m/s² downward.
11. Q: What is the velocity attained by a falling body when the force of air resistance balances its weight?
A: Terminal Velocity
Explanation: At this velocity, net force = 0, hence acceleration = 0.
12. Q: What is the shape of the velocity–time graph for uniform acceleration?
A: Straight Line
Explanation: Constant acceleration means velocity changes linearly with time.
13. Q: What does the area under the velocity–time graph represent?
A: Displacement
Explanation: Area = velocity × time = displacement.
14. Q: What does the slope of a distance–time graph give?
A: Speed (or Velocity)
Explanation: The slope shows how position changes with time.
15. Q: What is the displacement of a body returning to its starting point?
A: Zero
Explanation: Initial and final positions are the same.
16. Q: What is the path followed by a projectile called?
A: Parabola
Explanation: Projectile motion combines horizontal uniform motion and vertical accelerated motion.
17. Q: Which component of velocity remains constant in projectile motion?
A: Horizontal Component
Explanation: No acceleration acts horizontally (neglecting air resistance).
18. Q: At what angle is the range of a projectile maximum?
A: 45°
Explanation: Range ( R = \frac{u^2 \sin2θ}{g} ) is maximum when sin2θ = 1 (i.e., θ = 45°).
19. Q: What is the time taken by a projectile to reach its maximum height?
A: t = (u sinθ) / g
Explanation: At maximum height, vertical velocity becomes zero.
20. Q: What is the maximum height of a projectile?
A: H = (u² sin²θ) / (2g)
Explanation: Derived using vertical motion under gravity.
21. Q: What is the total horizontal distance covered by a projectile called?
A: Range
Explanation: ( R = \frac{u^2 \sin2θ}{g} ). It depends on angle and initial speed.
22. Q: What type of motion occurs when an object moves with constant speed in a circle?
A: Uniform Circular Motion
Explanation: Speed remains constant but direction continuously changes.
23. Q: What is the acceleration directed towards the centre in circular motion called?
A: Centripetal Acceleration
Explanation: ( a = v^2 / r ); it keeps the body moving in a circle.
24. Q: What is the rate of change of angular displacement called?
A: Angular Velocity
Explanation: ( ω = Δθ / Δt ); measured in radians per second.
25. Q: A body is always at rest with respect to whom?
A: Itself
Explanation: An object’s position relative to itself never changes.
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