Worksheets With Solutions: Time and Motion Class 7 Worksheet Science Chapter 9

Section A: Multiple Choice Questions

Correct Answer is Option (b)
Christiaan Huygens, a Dutch physicist, invented the pendulum clock in 1656. The pendulum clock was a major improvement over existing timekeeping devices and became the most accurate timekeeper for nearly 300 years.

Q.2. The world's largest sundial is located in which country?
(a) India
(b) China
(c) Egypt
(d) Mexico

Correct Answer is Option (a)
The world's largest sundial is located in Jaipur, India. The sundial, known as the Jantar Mantar, was built in the early 18th century and was used to measure time and astronomical observations.

Q.3. What is the formula for calculating speed?
(a) Speed = Distance × Time
(b) Speed = Time ÷ Distance
(c) Speed = Distance ÷ Time
(d) Speed = Time × Distance

Correct Answer is Option (c)
The formula for calculating speed is speed = distance ÷ time. This formula gives the rate at which an object is moving, in units of distance per unit of time.

Q.4. What is the SI unit of speed?
(a) Kilometer
(b) Meter
(c) Second
(d) Meter per second

Correct Answer is Option (d)
The SI unit of speed is meter per second (m/s). This unit expresses the speed of an object in meters traveled per second of time.

Q.5. What is uniform motion?
(a) Motion with constant speed and direction
(b) Motion with changing speed and direction
(c) Motion with constant speed but changing direction
(d) Motion with changing speed but constant direction

Correct Answer is Option (a)
Uniform motion is motion with a constant speed and direction. In this type of motion, the object travels the same distance in the same amount of time, without changing its speed or direction.

Section B: Short Questions

Measuring time is important in human history because it helps in organizing daily activities, tracking seasons and lunar phases, and developing calendars and time-keeping devices.

Q.2. Name two ancient civilizations that developed methods to measure time.

Two ancient civilizations that developed methods to measure time are the Egyptians and the Greeks.

Q.3. What are the different instruments used to measure time?

The different instruments used to measure time are clocks, watches, sundials, hourglasses, and water clocks.

Q.4. Explain the concept of simple pendulum.

A simple pendulum consists of a small, heavy object (the pendulum bob) suspended from a light, flexible string or rod. When the pendulum is set in motion, it swings back and forth in a regular pattern.

Q.5. What is the difference between slow and fast motion?

Slow motion refers to motion that is slower than normal, while fast motion refers to motion that is faster than normal.

Section C: Fill in the Blanks

Jantar Mantar
Jantar Mantar is a collection of architectural astronomical instruments built by the Rajput king Sawai Jai Singh II in the 18th century. Among these instruments, the sundial is the most prominent one. It is made of marble and stands at a height of 27 meters. It has a shadow that moves at a speed of 1 mm per second, making it the largest sundial in the world. 

Q.2. ___________ is the process of determining the duration or interval between two events.

Time Measurement
Time measurement is the process of quantifying the duration or interval between two events. It is used in various fields such as science, engineering, and commerce. Time is measured in seconds, minutes, hours, days, weeks, months, and years. 

Q.3. A ___________ is used to measure the time interval accurately.

Stopwatch
A stopwatch is a handheld device used to measure the time interval accurately. It has a start and stop button that can be used to start and stop the timer when needed. It is commonly used in sports to measure the time taken by athletes to complete a task. 

Q.4. The ___________ is a simple device used to measure time using periodic motion.

Simple Pendulum
The simple pendulum is a device that consists of a weight suspended from a pivot point so that it can swing back and forth. It is used to measure time using periodic motion. The time taken by the pendulum to complete one cycle is called its period, and it depends on the length of the pendulum and the acceleration due to gravity. 

Q.5. ___________ measures the rate at which an object moves.

Speed
Speed is defined as the rate at which an object moves. It is calculated by dividing the distance traveled by the time taken to travel that distance. The unit of speed is meters per second (m/s) or kilometers per hour (km/h). It is an essential parameter in physics and is used to describe the motion of objects. 

Section D: Match the Column

1. Sundial: Sundial measures time using the movement of the sun's shadow. It consists of a flat surface with markings indicating the hours of the day, and a gnomon that casts a shadow onto the surface. As the sun moves across the sky, the shadow shifts and indicates the time of day.
2. Water clock: Water clock measures time using the flow of water. It consists of a container with markings indicating the hours of the day and a small opening that allows water to flow out at a steady rate. As the water level drops, the time can be read from the markings.
3. Sand clock: Sand clock measures time using the flow of sand. It consists of two glass bulbs connected by a narrow neck and filled with sand. As the sand flows from one bulb to the other, it measures a specific amount of time.
4. Pendulum clock: Pendulum clock measures time using the oscillation of a pendulum. It consists of a pendulum that swings back and forth at a constant rate and controls the movement of the clock's gears.

Section E: True or False

False
The importance of measuring time dates back to ancient civilizations. From the sundial of ancient Egypt to the water clock of ancient Greece, various methods have been used throughout history to measure time accurately.

Q.2. The sundial is a modern invention.

False

The sundial is an ancient invention used to measure time. It is believed to have been invented in ancient Egypt around 1500 BCE and was widely used in many cultures throughout history.

Q.3. A simple pendulum is used to measure the time interval accurately.

True
A simple pendulum is a reliable tool used to measure the time interval accurately. The time period of a pendulum depends on its length and gravity and can be used to measure time with great precision.

Q.4. Speed detection cameras are used to measure the distance travelled by a vehicle.

False
Speed detection cameras are used to measure the speed of a vehicle. They work by using sensors to detect the time it takes for a vehicle to travel a known distance, and then calculate its speed based on that information. 

Q.5. Uniform motion is when an object moves with a constant speed.

True
Uniform motion is when an object moves with a constant speed. This means that the object covers equal distances in equal intervals of time, and its velocity remains constant. It is an important concept in physics and is used to describe many real-world phenomena.