A. Choose the correct option.
1.Early boats used this for travel across waterways.
a. Wind energy and water currents. b. Steam engines
c. Petrol engines d. Diesel engines
Answer: a. Wind energy and water currents
2.This is not a standard unit.
a. Inch b. metre c. hand span d. centimetre
Answer: c. Hand span
3.This is not a reliable measurement
a. Measurement based on body parts. b Measurement using a ruler c. Measurement using a ruler scale d. Measurement using a measuring tape.
Answer: a. Measurement based on body parts
4.A millimetre is
a. thousand times a meter b.one-hundredth of a meter.
c.one- thousandth of a meter. d one-tenth of a meter
Answer: c. One-thousandth of a meter
5. This type of motion in which all parts of the body in motion move by the same distance in a given time
a. Periodic motion. b Random motion c Translational motion d. Rotational motion.
Answer: c. Translational motion
B. Fill in the blanks with correct words.
1.The inch is a ______ (standard/non-standard) unit of length.
Answer: The inch is a non-standard unit of length.
2.The SI unit of length is ______ (yard/metre)
Answer: The SI unit of length is meter.
3.________ (Standard/Non-standard) unit do not vary from person to person and place
Answer: Standard units do not vary from person to person and place.
4.The length of the outstretched arms is called ____ (cubit/fathom)
Answer: The length of the outstretched arms is called fathom.
5. Rectilinear motion is motion along a _____ (straight/curved) line.
Answer: Rectilinear motion is motion along a straight line.
6.__________ (Rotational /Periodic) motion repeats after equal intervals of time.
Answer: Periodic motion repeats after equal intervals of time.
c. Match the following.
| Column A | Column B |
| 1.Modern transport | a. Steam engine |
| 2.Ancient transport | b. Unit of length |
| 3.Led to railways | c. Airplane |
| 4. Kilometre | d. About an axis |
| 5. Rotation | e. Raft |
Answer:
| Column A | Column B |
| 1.Modern transport | a. Airplane |
| 2.Ancient transport | b. Raft |
| 3.Led to railways | c. Steam engine |
| 4. Kilometre | d. Unit of length |
| 5. Rotation | e. About an axis |
D. Identify the type(s) of motion in the following.
1. A spinning top.
Answer: Rotational motion
2. The steering wheel of a vehicle.
Answer: Rotational motion
3.The vibrating string of guitar.
Answer: Periodic motion
4.A bus moving on a straight road.
Answer: Rectilinear (Translational) motion
5.A fish moving in the pond.
Answer: Random motion
6.A basketball thrown up in the air.
Answer: Translational motion
7.The hands of a wall clock.
Answer: Rotational and periodic motion
8. The turning of a door knob.
Answer: Rotational motion
9. An athlete in 100 m dash.
Answer: Rectilinear motion
10.The wheels of a moving car.
Answer: Rotational motion
E. Give two examples for each of the following.
1.Means of transport used by early humans
Answer: Raft, Cart
2.Modern vehicles of transport.
Answer: Car, Airplane
3.Non-standard units of length.
Answer: Hand span, Foot length
4.Standard units of length
Answer: Meter, Centimeter
5.Instruments used for measuring length.
Answer: Ruler, Measuring tape
6.Objects undergoing rotational motion
Answer: Fan, Wheel
7.Objects in periodic motion.
Answer: Pendulum, Swing
F. Explain the following terms.
1.Length
Answer: Length is the measurement of how long something is from one end to the other.
2.Measurement
Answer: Measurement is finding out the size, amount, or quantity of something using a standard unit.
3.Hand span
Answer: Hand span is the distance between the tip of the thumb and the tip of the little finger when the hand is stretched out.
4.Unit
Answer: A unit is a fixed quantity used to measure things, like meters or kilograms.
5.SI system of units.
Answer: The SI (International System of Units) is a system of measurement that is used all over the world to keep measurements the same, like meters for length.
6.Translational motion
Answer: Translational motion is when an object moves from one place to another, covering a distance.
7. Rectilinear motion
Answer: Rectilinear motion is when an object moves in a straight line.
8. Periodic motion
Answer: Periodic motion is a type of motion that repeats after equal intervals of time, like the swinging of a pendulum.
G. Answer the following.
1.Explain why it is important to adopt a common set of standard units.
Answer: Using standard units is important because it helps everyone measure things the same way. This makes it easy to understand, compare, and share measurements with others without confusion.
2.What are the precautions one should take while measuring a length with a ruler?
Answer: When measuring with a ruler, make sure to place the ruler straight along the length you’re measuring. Start measuring from the zero mark and look directly at the measurement to avoid mistakes.
3.Is it possible to measure the length of a curved line? Explain.
Answer: Yes, it is possible to measure a curved line by using a flexible measuring tape or a piece of string to trace along the curve. Then, the length of the string can be measured with a ruler.
4.Can an object have more than one type of motion? Give an example.
Answer: Yes, an object can have more than one type of motion. For example, the wheels of a moving car show both rotational motion (wheels spinning) and translational motion (car moving forward).