Measurement of Time and Motion

Class 7 > Science > Curiosity (New Book) > Measurement of Time and Motion

LAQ for Chapter 8 Measurement of Time and Motion Class 7 Science NCERT

Important Questions

1

Q1: State different types of motion?

Answer

Following are different types of motion:
•Translatory Motion: - In Translatory motion the particle moves from one point in space to another. This motion may be along a straight line or along a curved path.
• Rectilinear motion : Motion along a straight line is called rectilinear motion. Example: A car moving on a straight road
• Curvilinear motion: Motion along a curved path is called curvilinear motion. Example: A car negotiating a curve
• Rotatory Motion : In rotatory motion, the particles of the body describe concentric circles about the axis of motion
• Vibratory Motion: In vibratory motion the particles move to and fro about a fixed point.
LAQ

2

Q2: A simple pendulum takes 15 seconds to complete 5 oscillations. What is the time period of pendulum?

Answer

The time taken by pendulum to complete 1 oscillation is called time period
The time taken by pendulum to complete 5 oscillation = 15sec
The time taken by pendulum to complete 1 oscillation = 15/5= 3 sec
So time period = 3 sec
LAQ

3

Q3: The odometer of a car reads 57321.0 km when the clock shows the time 08:30 AM. What is the distance moved by the car, if at 08:50 AM, the odometer reading has changed to 57336.0 km? Calculate the speed of the car in km/min during this time. Express the speed in km/h also.

Answer

Initial reading of car odometer= 57321.0 km
Final reading of car odometer= 57336.0 km
Time at the time of Initial reading= 08:30 AM
Time at the time of Initial reading= 08:50 AM
Distance travelled by the car = 57336.0 km - 57321.0 km = 15 Km
Time taken by the car to cover distance = 08:50 AM -08:30 AM = 20 m
Speed of the car in Km/m = 15 km/20m
= .75 Km/m
Speed of the car in Km/h = 15 km/20m X 60 = 45 Km/h
LAQ

4

Q5: A car moves with a speed of 40 km/h for 15 minutes and then with a speed of 60 km/h for the next 15 minutes. The total distance covered by the car is:

Answer

Distance covered by the car with a speed of 40 km/h in 15 minutes = Speed * Time 
= (40 Km/h /60 minutes) * 15 minute = 10 Km 
Distance covered by the car with a speed of 40 km/h in 15 minutes = Speed * Time 
= (60 Km/h /60 minutes) * 15 minute = 15 Km
Total distance covered by the car =(10 + 15 )km = 25 Km
LAQ

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