Science Worksheet (Set 9)
Topic: Motion and Time
Grade: VII
Q1. Answer briefly:
a. Under what condition is the distance-time graph of an object a horizontal line parallel to the time axis?
When the object is at rest (not moving), the distance remains constant, resulting in a horizontal distance-time graph.
b. Name an instrument that indicates the speed of the vehicle.
Speedometer
c. Name two important devices used in ancient times to measure time.
Sundial, Hourglass (Sand Clock)
d. What is the maximum displacement of the bob from its mean position called?
Amplitude
e. Name the clock used for the accurate measurement of time.
Atomic clock
f. The speed of a moving object is determined to be 0.06 m/s. This speed is equal to:
| Options | Conversion |
|---|---|
| 2.16 km/h | ❌ |
| 1.08 km/h | ❌ |
| 0.216 km/h | ✅ Correct Answer |
| 0.0216 km/h | ❌ |
g. What type of motion is represented by the following?
| Scenario | Type of Motion |
|---|---|
| The tuning fork | Vibratory motion |
| A stone thrown up in the air | Projectile motion |
| A train moving at various speed limits | Non-uniform motion |
| A bullet shot from a pistol | Uniform motion (straight-line motion with high speed) |
Q2. Answer the following questions:
a. A car is running at a speed of 60 km/h. How much time will it take to cover a distance of 27 km?
Solution:
\[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} \] \[ = \frac{27 \text{ km}}{60 \text{ km/h}} = 0.45 \text{ hours} = 27 \text{ minutes} \] Answer: The car will take 27 minutes to cover 27 km.b. Differentiate between uniform motion and non-uniform motion with the help of a graph.
| Uniform Motion | Non-Uniform Motion |
|---|---|
| The object covers equal distances in equal intervals of time. | The object covers unequal distances in equal intervals of time. |
| Distance-time graph is a straight line. | Distance-time graph is a curved line. |
| Example: A car moving at a constant speed. | Example: A car speeding up or slowing down. |