🌟 Class
7 Science Curiosity – Chapter 8 Solutions
⏱️ Measurement of Time and
Motion | Amresh Academy
📝 🔹 Let Us
Enhance Our Learning
1. Calculate the speed of a car that travels 150
metres in 10 seconds. Express your answer in km/h.
✅ Final
Answer: 15 m/s or 54 km/h 🚗
2. A runner completes 400 metres in 50 seconds.
Another runner completes the same distance in 45 seconds. Who has a greater
speed and by how much?
➡️
Difference = 8.89 – 8 = 0.89 m/s
✅ Runner
2 is faster by 0.89 m/s 🥇
3. A train travels at a speed of 25 m/s and
covers a distance of 360 km. How much time does it take?
✅ Final
Answer: 4 hours 🚆
4. A train travels 180 km in 3 h. Find its speed
in:
👉 Answer:
(i) Speed = 180 / 3 = 60 km/h
(ii) Convert → 60 ×
(5/18) = 16.67 m/s (approx.)
5. The fastest galloping horse can reach the
speed of approximately 18 m/s. How does this compare to the speed of a train
moving at 72 km/h?
➡️ 20 m/s
> 18 m/s
✅ Train
is faster 🚆
6. Distinguish between uniform and non-uniform
motion using the example of a car moving on a straight highway with no traffic
and a car moving in city traffic.
👉 Answer:
✍️ 🔹 Very
Short Answer Type Questions
What is the SI unit of time?
👉 Second
(s) ⏱️
What does a speedometer measure?
👉 Speed
of vehicle 🚗
What is one oscillation of a pendulum?
👉 One
complete swing 🔄
Name a device used in ancient times to measure
time.
👉
Sundial / water clock ⏳
What is meant by uniform motion?
👉 Equal
distance in equal time
🧠 🔹 Short
Answer Type Questions
What does a simple pendulum consist of?
👉 Bob +
thread + support
What is the use of an odometer in vehicles?
👉
Measures total distance 🚗
Why do we use quartz or atomic clocks today?
👉 High
accuracy ⏱️
How was time measured before mechanical clocks
were invented?
👉
Sundial, water clock, candle clock
Why is speed called a derived quantity?
👉 From
distance & time
📖 🔹
Descriptive Answer Type Questions
How can you find the time period of a simple
pendulum?
👉 Time
for 10 oscillations ÷ 10 ⏱️
Explain the importance of accurate timekeeping
in sports and medicine.
What is meant by non-uniform motion? Give one
example.
What are the three main ways time is measured
today?
👉
Mechanical, Quartz, Atomic clocks
How does the length of a pendulum affect its
time period?
👉 Longer
length → more
time ⏳
🚀 🔹
Exploring Questions
Why is measuring speed important in everyday
life?
👉 Travel
planning + safety 🚗
Can the same pendulum be used at different
places to measure time accurately?
👉 Slight
variation due to gravity 🌍
How did Galileo’s observation of a lamp lead to
time measurement discoveries?
👉 Led to
pendulum clocks ⏱️
What makes atomic clocks more accurate than
pendulum clocks?
👉 Atomic
vibrations = highly precise ⚛️
How does understanding motion help in space
exploration?
👉
Accurate navigation 🚀
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