Page 116 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

6. The metallic ball in a simple pendulum is called the ..................... of the pendulum.

Ans: bob

7. The distance-time graph for the motion of an object moving with a constant speed is
a ..................... .
Ans: straight line

C. State whether the following statements are true (T) or false (F).

1. Motion along a curved path is called curvilinear motion.
2. The time period of a given pendulum is not constant.
3. Speed = Distance/Time

4. Odometer is the device used to measure speed.

5. For a body in non-uniform motion, the graph is not a straight line.
6. Distance between two cities is measured in km.
7. The speed of a train is expressed in m/h.

Ans: 1. (T) 2. (F) 3. (T) 4. (F) 5. (T) 6. (T) 7. (F)
D. State the type of motion.

Example of motion Type of motion
1. Movement of our chest while breathing Periodic Motion

2. Pedals of a cycle Rotational Motion

3. Motion of a pendulum Periodic Motion
4. Motion of a spinning wheel Rotational Motion
5. A stone falling from a certain height Rectilinear Motion

6. A car moving in a straight line Rectilinear Motion

7. A plucked string of a guitar Vibrational Motion
E. Very short-answer questions.
1. What is the basic unit of time?

Ans: Seconds (s).

2. What is a speedometer?
Ans: It is a device used to measure the speed of a vehicle in km.
3. Define speed and write its SI unit.

Ans: Speed is defined as the distance covered by the object per unit time.

Its SI unit is m/s.
4. Convert 6 m/s into km/h.
Ans: 6 m/s ⇒ km/h

So, we will multiply it by 18/5.

6 x 18 = 6 x 3.6 = 21.6 km/h
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