Introduction to Measurement of Time and Motion
Looking for a Class 7 Science Measurement of Time and Motion worksheet with answers? This practice worksheet helps students revise important concepts from Chapter 8 through multiple-choice questions, assertion–reason questions, short-answer questions and numerical problems.
Practise questions on simple pendulums, SI units of time, traditional clocks, speed, average speed, unit conversions, and uniform and non-uniform motion. These exam-oriented questions are useful for school tests, revision and science practice.
- Time period and oscillations of a simple pendulum
- Correct SI units and symbols for time
- Ghatika-yantra and sundials
- Speed, distance, time and average speed numericals
- Uniform and non-uniform motion
Instructions: Attempt all questions before checking the answer key. Show calculations and write the correct units in numerical answers.
Class 7 Science Chapter 8: Measurement of Time and Motion Worksheet with Answers
Exam-ready practice questions to strengthen your concepts and calculation skills.
SECTION A: Multiple Choice Questions
SECTION B: Assertion–Reason Questions
Choose the correct option for Q6–Q8:
Assertion (A): The water clock in which water flows out of a vessel was not very accurate.
Reason (R): As the water level drops, the rate of flow decreases.
Assertion (A): The average speed of a bus moving in city traffic is found by dividing the total distance by the total time taken.
Reason (R): A bus in city traffic moves with a constant speed throughout its journey.
Assertion (A): A sundial cannot be used to tell the time at night.
Reason (R): A sundial shows local solar time, which needs a correction to get Indian Standard Time.
SECTION C: Short Answer Questions
SECTION D: Long Answer Questions
(i) Find the time taken for each part of the journey.
(ii) Calculate the average speed of the train for the whole journey.
(iii) Is the train’s motion uniform or non-uniform? Give a reason.
(i) Who has the greater speed? Show your calculation in m/s.
(ii) Why can we not decide who is faster by comparing only their times, 12.5 s and 3 minutes?
(iii) Prerna says, “My speed was 8 m/s throughout the race.” Why is this statement unlikely to be fully correct? What should she have said?
Answer Key with Explanations
Attempt the questions first. Open the answer key when you are ready to check your work.
Reveal all answers and explanations
Section A: MCQs
| Q | Answer | Explanation |
|---|---|---|
| 1 | (c) | The time period depends on pendulum length and gravitational acceleration, not bob mass under the small-angle approximation. |
| 2 | (b) | The correct SI symbol for second is lowercase s. |
| 3 | (c) | 6 h = 360 min; 360 ÷ 24 = 15 ghatis. |
| 4 | (b) | 3 min = 180 s; speed = 900 ÷ 180 = 5 m/s. |
| 5 | (b) | 15 km in 15 min gives 15 ÷ 0.25 = 60 km/h. Equal distances in equal time intervals indicate uniform motion. |
Section B: Assertion–Reason
| Q | Answer | Explanation |
|---|---|---|
| 6 | (a) | Both are true. As the water level drops, the outflow rate changes, reducing the accuracy of the clock. |
| 7 | (c) | The assertion is true, but the reason is false. A bus in city traffic generally changes speed. |
| 8 | (b) | Both are true, but the reason does not explain the assertion. A sundial needs sunlight to cast a shadow. |
Section C: Short Answers
Q9. The time period is the time taken to complete one oscillation.
Time period = Total time ÷ Number of oscillations = 24 ÷ 12 = 2 s.
Q10. 5 hrs = 5 h; 30 sec = 30 s; 45 Min = 45 min.
Q11. 108 km/h = 108 × 1000 ÷ 3600 = 30 m/s.
Distance = speed × time = 30 × 15 = 450 m.
Section D: Long Answers
Q12 (i). First part: 60 ÷ 40 = 1.5 h. Second part: 60 ÷ 60 = 1 h.
(ii). Total distance = 120 km; total time = 2.5 h.
Average speed = 120 ÷ 2.5 = 48 km/h.
(iii). The motion is non-uniform because the speed changes from 40 km/h to 60 km/h.
Q13 (i). Prerna: 100 ÷ 12.5 = 8 m/s. Arjun: 1.5 km = 1500 m and 3 min = 180 s; 1500 ÷ 180 ≈ 8.33 m/s. Arjun has the greater average speed by approximately 0.33 m/s.
(ii). They cover different distances, so time alone cannot establish who is faster. Compare distance travelled per unit time.
(iii). A runner's speed may change during the race. Prerna should say her average speed was 8 m/s.
Quick Revision: Important Formulas
Speed = Distance ÷ Time
Distance = Speed × Time
Time = Distance ÷ Speed
Average speed = Total distance ÷ Total time
Time period = Total time ÷ Number of oscillations
- 1 hour = 60 minutes = 3600 seconds.
- 1 kilometre = 1000 metres.
- km/h to m/s: multiply by 5/18.
- m/s to km/h: multiply by 18/5.
Frequently Asked Questions
What topics does this Class 7 Science worksheet cover?
It covers time measurement, pendulums, time units, traditional clocks, speed, average speed and motion.
Does the worksheet include answers?
Yes. Expand the answer key to view explanations and numerical solutions.
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