Malini Sheshdari Solutions for Chapter: Motion and Time, Exercise 3: STEP OUT

Arrange the following time measuring devices in the order of the most ancient to the most recently developed.

wrist watch, atomic clock, pendulum clock, water clock, digital clock, stopwatch

What is the working principle of a water clock?

Is a water clock more accurate than a sand clock? Explain your answer.

Rahul's family went on a trip from New Delhi to Agra by car. The distance between the cities is $210 \mathrm{km}$. After travelling for $1.5 \mathrm{h}$, they stopped for a snack for $0.5 \mathrm{h}$. After reaching Agra, they took a break for $1 \mathrm{h}$ to have lunch and left for sightseeing at $2.00 \mathrm{pm}$. They later returned to the hotel at a certain time. They immediately left for New Delhi and drove back without stopping anywhere. They got home at exactly $10 \mathrm{pm}$.

If the average speed of the car was $70 \mathrm{km}/\mathrm{h}$ on both trips to and from Agra, at what time in the morning did Rahul's family start from Delhi?

Rahul's family went on a trip from New Delhi to Agra by car. The distance between the cities is $210 \mathrm{km}$. After travelling for $1.5 \mathrm{h}$, they stopped for a snack for $0.5 \mathrm{h}$. After reaching Agra, they took a break for $1 \mathrm{h}$ to have lunch and left for sightseeing at $2.00 \mathrm{p}.\mathrm{m}$. They later returned to the hotel at a certain time. They immediately left for New Delhi and drove back without stopping anywhere. They got home at exactly $10 \mathrm{p}.\mathrm{m}$. The average speed of the car was $70 \mathrm{km}/\mathrm{h}$ on both trips to and from Agra.

Complete the table.