Question

21. Which of the two measures time more accurately: a quartz clock or a pendulum clock ?
2. Which of the two requires an electric cell for its working : a quartz clock or a pendulum clock ?
23. A boy riding a bicycle covers a distance of 10 m in 40 s. What is the speed of the boy ?
4. A bus takes 30 minutes to travel a distance of 25 kilometres. Calculate the speed of the bus in km/h.
15. What is a speedmeter ?​

Answer 1

Answer:

2 1) Quartaz

2)pendulum clock

3)0. 25m/s is the speed of the boy.

4)Time taken by the bus =30min =1/2 hour

distance travelled by the bus =25km

therefore,

Speed= distance/time =50km/h

5)A speedometer or a speed meter is a gauge that measures and displays the instantaneous speed of a vehicle.