Class 9 Science Motion

Class 9 Science Motion

 

Class 9 Science Motion Fill in the blanks , MCQ and True false .

 

Fill in the Blanks

1. Motion is a change in __________ of an object. Answer: position

2. The shortest distance between initial and final position is called __________.
Answer: displacement

3. If an object covers equal distances in equal time, it is in __________ motion.
Answer: uniform

4. Speed has only magnitude, so it is a __________ quantity. Answer: scalar

5. Velocity is speed with __________. Answer: direction

6. The SI unit of speed is __________. Answer: m/s (metres per second)

7. The rate of change of velocity is called __________. Answer: acceleration

8. The motion of a body moving in a circular path at constant speed is called __________ motion. Answer: uniform circular

9. An odometer measures the __________ travelled by a vehicle. Answer: distance

10. A speed-time graph with a straight line parallel to the time axis shows __________ motion. Answer: uniform

11. The area under a velocity-time graph gives the __________ travelled. Answer: distance

12. When an object returns to its starting point, displacement is __________.
Answer: zero

13. The formula for average speed is total distance divided by total __________.
Answer: time

14. The formula for acceleration is (final velocity – initial velocity) divided by __________. Answer: time

15. The SI unit of acceleration is __________. Answer: m/s²

 

Multiple Choice Questions

 

1. What is the SI unit of speed?
(a) m²/s (b) m/s (c) km/h (d) cm/s
Answer: (b) m/s

 

2. Displacement depends on:
(a) Path taken
(b) Time taken
(c) Initial and final positions
(d) Speed
Answer: (c) Initial and final positions

 

3. What type of motion does a car on a straight road with constant speed have?
(a) Uniform motion
(b) Circular motion
(c) Oscillatory motion
(d) Irregular motion
Answer: (a) Uniform motion

 

4. Velocity is a __________ quantity.
(a) Scalar
(b) Directionless
(c) Vector
(d) Constant
Answer: (c) Vector

 

5. Which of these quantities is always non-negative?
(a) Displacement
(b) Speed
(c) Acceleration
(d) Velocity
Answer: (b) Speed

 

6. What does the odometer in a car measure?
(a) Speed
(b) Velocity
(c) Distance
(d) Acceleration
Answer: (c) Distance

 

7. When an object returns to its starting point, the displacement is:
(a) Positive
(b) Negative
(c) Zero
(d) Infinite
Answer: (c) Zero

 

8. The rate of change of velocity is:
(a) Speed
(b) Velocity
(c) Distance
(d) Acceleration
Answer: (d) Acceleration

 

9. What is the shape of a distance-time graph for uniform motion?
(a) Curved line
(b) Zigzag line
(c) Straight line
(d) Dotted line
Answer: (c) Straight line

 

10. In uniform circular motion, which quantity changes continuously?
(a) Speed
(b) Direction
(c) Distance
(d) Time
Answer: (b) Direction

 

11. If velocity increases with time, the body is said to have:
(a) Uniform motion
(b) Negative acceleration
(c) Positive acceleration
(d) Zero acceleration
Answer: (c) Positive acceleration

 

12. Which of the following is a vector quantity?
(a) Distance
(b) Speed
(c) Acceleration
(d) Time
Answer: (c) Acceleration

 

13. What is the average speed of a car that travels 100 km in 2 hours?
(a) 20 km/h
(b) 25 km/h
(c) 50 km/h
(d) 60 km/h
Answer: (c) 50 km/h

 

14. What is uniform acceleration?
(a) Speed increases at random
(b) Velocity remains constant
(c) Acceleration remains the same over time
(d) Direction changes but speed remains the same
Answer: (c) Acceleration remains the same over time

True or False

1. Displacement can be zero even if distance is not. True

2. A body at rest has zero acceleration. True

3. Speed is always greater than or equal to velocity. True

4. A curved distance-time graph shows uniform motion. False

5. Displacement is a scalar quantity. False

6. The slope of a distance-time graph gives acceleration. False

7. The area under a velocity-time graph gives distance. True

8. Speed and velocity have the same SI unit. True

9. In circular motion, speed changes but direction does not. False

10. A straight horizontal line in a velocity-time graph shows zero acceleration.
True

11. When an object moves in a circle at constant speed, its velocity is also constant.
False

12. Negative acceleration means the object is speeding up. False

13. Time is a vector quantity. False

14. A uniformly moving object has zero acceleration. True

15. The average speed of an object is total distance divided by total time. True