Question

4.
what is the difference between rest and motion?
The odometer of a car reads 57421.0 km when the clock shows the time 9:20 am. What is the
distance moved by the car, if at 9:40 am the odometer reading has changed to 57439.0 km? Calculate
the speed of the car in km/min and km/h also.
HOTS Questions
1. How can the time period of a pendulum be increased or decreased?
2. Is it correct to say that both the hands of a clock move in a uniform circular motion?
Project Work
Visit the National Physical Laboratory (NPL), New Delhi to see the atomic clock and understand its
functioning
2. Make a model of a sand clock which can measure a time interval of 5 minutes.
THINGS TO DO
Collect information about different time measuring devices used in different parts of the world before the
pendulum cocks became popular. Bring your information to the class and share it with your friends.​

Answer 1

Answer:

1. what is the difference between rest and motion?

• A body is said to be at rest if doesn't change it's position with respect to its surroundings while a body is said to be in motion if it continuously changes it's position with respect to its surroundings...

1. The odometer of a car reads 57421.0 km when the clock shows the time 9:20 am. What is the distance moved by the car, if at 9:40 am the odometer reading has changed to 57439.0 km?Calculate the speed of the car in km/min and km/h also.

• Initial reading of the odometer of the car = 57321.0 km
• Final reading of the odometer of the car = 57336.0 km
• Distance covered by the car = Final reading of the odometer of the car - Initial reading of the odometer of the car
• = 57336.0 - 57321.0 = 15 km
• The given car starts at 8:30 a.m. and stops at 8:50 a.m.
• Therefore, time taken by the car to cover the distance is (8:50 — 8:30) min = 20 min
• Distance covered by the car =15 km
• Time taken by the car = 20 min

1. How can the time period of a pendulum be increased or decreased?

• Time period of a pendulum can be increased or decreased by changing th elength of the string of pendulum. The time period of the pendulum decreases as the length of the string increases and it increases as the length of the string decreases, hence time period is inversely proportional to the length of the string.

1. Is it correct to say that both the hands of a clock move in a uniform circular motion?

• It is possible for a body to move in a circular path with uniform speed as long as it is travelling equal distances in equal intervals of time. But the velocity of the body moving in a circle with uniform speed is not uniform because the direction of motion is constantly changing.

1. Project WorkVisit the National Physical Laboratory (NPL), New Delhi to see the atomic clock and understand its functioning

• you can ask from goggle you will get your answer very very very well

1. Make a model of a sand clock which can measure a time interval of 5 minutes.
2. THINGS TO DO
3. Collect information about different time measuring devices used in different parts of the world before the
4. pendulum cocks became popular. Bring your information to the class and share it with your friends.

• Imagehttps://school.gradeup.co › collect-i...
• Web results
• Collect information about time measuring devices that were used in the ancient times in
• Open the link on google you get your answer

Hope this helpfull to you

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