A. Choose the Correct Answer

1. Which instrument uses the changing position of a shadow to measure time?

a) Hourglass    b) Sundial    c) Water clock    d) Stopwatch

2. The SI unit of time is:

a) hour    b) minute    c) second    d) day

3. The time taken by a pendulum to complete one oscillation is called its:

a) speed    b) time period    c) distance    d) frequency

4. The SI unit of speed is:

a) km/h    b) m/s    c) m/h    d) km/s

5. Which device measures the distance travelled by a vehicle?

a) Speedometer    b) Odometer    c) Stopwatch    d) Thermometer

6. An object covering equal distances in equal intervals of time is said to be in:

a) non-uniform motion    b) uniform motion    c) circular motion    d) random motion

B. Fill in the Blanks

1. 60 seconds = ______ minute.

2. 60 minutes = ______ hour.

3. The SI unit of time is ______.

4. The SI unit of speed is ______.

5. Speed is equal to distance divided by ______.

6. A device used to measure the speed of a vehicle is called a ______.

7. A device used to measure the distance travelled by a vehicle is called an ______.

8. The time taken by a pendulum to complete one oscillation is called its ______.

C. True or False

1. The SI unit of time is minute.

2. A sundial uses the position of a shadow to indicate time.

3. Speed is distance divided by time.

4. In uniform motion, an object covers unequal distances in equal intervals of time.

5. The time period of a pendulum depends on its length.

6. An odometer measures the speed of a vehicle.

7. A vehicle moving in city traffic generally shows non-uniform motion.

8. The symbol for second is s.

D. Match the Following

E. Answer in One or Two Sentences

1. What is meant by one oscillation of a pendulum?

2. What is the time period of a pendulum?

3. What is meant by speed?

4. What is uniform motion?

5. What is non-uniform motion?

6. Why is a railway timetable useful for studying motion?

7. What is the difference between a speedometer and an odometer?

8. Name two traditional devices used for measuring time.

F. Numerical Questions

1. A car travels 150 m in 10 s. Calculate its speed in m/s.

2. A runner covers 400 m in 50 s. Find the speed of the runner.

3. A train travels 100 km in 2 hours. Find its average speed in km/h.

4. A cyclist travels at 5 m/s for 20 seconds. Find the distance travelled.

5. A train travels at 60 km/h and covers a distance of 180 km. Find the time taken.

6. Convert 72 km/h into m/s.

7. Convert 10 m/s into km/h.

8. A car covers 60 km in the first hour, 70 km in the second hour and 50 km in the third hour. Is its motion uniform? Find its average speed.

G. Think and Apply

1. Two cars travel for the same amount of time. Car A covers 100 km while Car B covers 80 km. Which car is faster? Give a reason.

2. A child walks along a straight road at a constant speed. What type of motion does the child show?

3. A bus repeatedly stops and starts while travelling through a busy city. Is its motion likely to be uniform or non-uniform? Explain.

4. Two pendulums have the same length but different masses attached to their strings. Which pendulum would have nearly the same time period?

5. Why is a standard unit of time necessary for scientific measurements?

6. Why can the speed of a moving vehicle change even when it is travelling on a straight road?

H. Challenge Questions

1. A vehicle covers 200 m in 20 s. Another vehicle covers 300 m in 30 s. Compare their speeds.

2. A train travels 180 km in 3 h. Find its speed in km/h and m/s.

3. An object covers 20 m in the first 5 s and another 40 m in the next 5 s. Is its motion uniform? Give a reason.

4. A vehicle travels 2 km. It covers the first 500 m at 10 m/s and the next 500 m at 5 m/s. If the entire journey must be completed in 200 s, calculate the speed required for the remaining distance.

5. Explain why a pendulum can be useful for measuring time.

Quick Revision

• SI unit of time → second (s)
• 60 s → 1 min
• 60 min → 1 h
• Speed = Distance ÷ Time
• SI unit of speed → m/s
• Uniform motion → equal distances in equal intervals of time
• Non-uniform motion → unequal distances in equal intervals of time
• Speedometer → measures speed
• Odometer → measures distance
• Time period of pendulum → time for one oscillation