Track quiz
Thirteen quick questions. Use the table if you get stuck.
| Lesson | The rule |
|---|---|
| Repeats | A clock counts a repeat that has equal gaps. |
| Units of time | 60 s = 1 min. 60 min = 1 h. |
| Pendulum | The time period depends on the thread length. The bob's mass does not matter. |
| Speed | Speed is the distance covered divided by the time taken. |
| Units of speed | 1 m/s = 3.6 km/h. |
| Uniform motion | Uniform motion covers equal distances in equal times. |
| Average speed | Average speed is the total distance divided by the total time. |
| Old clocks | A sundial uses a moving shadow, so it needs sunlight. A water clock uses flowing water. An hourglass uses falling sand. A candle clock uses a burning candle. |
| Water clock marks | A draining jar loses water fast when it is full. It loses water slowly when it is nearly empty. So in a straight jar, marks for equal minutes are spaced unevenly. |
| How exact | A good clock gains or loses very little time. A quartz clock counts the vibrations of a crystal. An atomic clock drifts by about one second in millions of years. |
| Smallest tick | A clock cannot show a gap smaller than its smallest tick. To tell close times apart, use a smaller tick. |
| Timetable | Time taken is the arrival time minus the leaving time. Speed is the distance divided by that time. This is the average speed. |
Which of these can keep time?
How many minutes are in 3 h?
Two pendulums have the same thread length. One bob is heavy. One is light. What do you find?
A pendulum takes 20 s for 10 oscillations. What is its time period?
A cyclist covers 600 m in 40 s. What is the speed?
A speed is 25 m/s. What is it in km/h?
In each of four 5 s periods, a car covers 15 m. What kind of motion is it?
A car covers 180 km in 3 h. What is its average speed?
Which old clock needs sunlight to work?
A straight jar drains through a small hole. The level is marked every minute. How are the marks spaced?
Which clock gains or loses the least time?
A wall clock reads 12 s for two sprinters. A sports timer reads 12.46 s and 12.49 s. Why the difference?
A train leaves at 08:00 and reaches at 10:30. It covers 100 km. What is its speed?
Chapter 8 of your NCERT book is Measurement of Time and Motion. Read it this week.
Next: Life Processes in Animals.