Class 6 Science Chapter 7 MCQ

The motion which repeats itself after regular intervals of time, is called periodic motion. When an object moves along a circular path, it is called circular motion. The movement of seconds’ hand of a watch is repeated after regular intervals of time, so the motion of seconds’ hand of a watch is an example of periodic motion. Similarly, the movement of the seconds’ hand of a watch or clock on the dial is an example of circular motion. As the watch does not move from one place to another by itself but the hands of watch or clock keep on rotating on its dial.

The distance between Delhi and Mumbai is expressed in kilometer because other units like meter, centimeter and decameter are so small to express this big distance.

The SI unit of measuring length is meter. 10,00,000 millimeter makes 1 kilometer. 1,00,000 centimeter makes 1 kilometer. 1,000 meter makes 1 kilometer. Thus, millimeter is the smallest unit of length and kilometer is the largest unit of length. But the SI unit of measuring length is “meter”. Note: When we measure the distance between celestial bodies (stars, galaxy, asteroids etc.) we use light year.

Here, are all the statements are incorrect. Hence, your answer will be option [D]. In option [A]: If an object moves fairly fast, then its movement or motion can be observed easily. In option [B]: If an object moves very slowly, then it becomes very difficult to observe its movement immediately. In option [C]: When an object is stationary it is said to be at rest.

We have to convert the height of 1.56 m into mm. Now, we know that: 1 meter = 1000 mm So, 1.56 m = 1000 x 1.56 mm = 1560 mm Thus, a height of 1.56 m is equal to 1560 millimeter

Motion in a straight line is called rectilinear motion. Some examples of rectilinear motion are motion of a vehicle on a straight road, motion of a train on a straight track, motion of a falling stone, motion of a ball rolling on ground etc. Rectilinear motion takes place in a fixed direction.

When an object turns or spins about a fixed axis, it is called rotational motion. When an object moves along a straight-line path it is called rectilinear motion. When a bicycle moves on a straight road, turning of bicycle wheel shows the rotational motion. And as it goes in a straight road, it exhibits the rectilinear motion.

Here, are all the statements are correct. Hence, your answer will be option [D].

Paheli moves in a straight path from A to C and from C to A. So, the motion is rectilinear, further Paheli moves in a periodic motion because she makes 5 rounds in the same way and crosses point B in each round, after a regular a time interval. So, her motion is rectilinear and periodic.

As we know that: 1000 meter makes 1 kilometer 1 meter = 1/1000 kilometer 1425 meter = 1/1000 x 1425 kilometer = 1.425 kilometer Thus, a distance of 1425 meter is equal to 1.425 kilometer.

Here, are all the statements are correct. Hence, your answer will be option [D].

When a ball is moving on the ground, it is rotating as well as moving forward on the ground. So, a ball rolling on the ground has two types of motion, rotational motion as well as a rectilinear motion.

A pencil or a notebook has small length which is much smaller than a meter. It is inconvenient to express such a small length in terms of meter. So, the length of small objects is measured in centimeter. Thus, in order to measure the length of a pencil or notebook, we use centimeter as the unit of length. A centimeter is one-hundredth of a meter.

If we consider a merry-go-round as a whole, then it shows rotational motion because it turns on an axle. But the outer part of merry-go-round (on which children sit) shows circular motion. So, a merry-go-round has two types of motion at the same time, rotational motion and circular motion.

Here, are all the statements are correct. Hence, your answer will be option [D].

The various types of devices which are commonly used for measuring length are meter scale and measuring tape. If the object is round then we have to use a measuring tape for making measurement of length. As the girth of a tree can be measured only by using a measuring tape because a measuring tape can be bent around the tree. And plastic ruler, a meter scale or a meter rod is made of metal and cannot be bend at all.

The earth moves around the sun, so it has circular motion. The earth repeats its motion around the sun after regular intervals of time (means one year), so it has periodic motion and the earth rotates on its axis, so it has also rotational motion. Thus, the earth has three types of motion at the same time, circular motion, periodic motion and rotational motion.

In circular motion and object as a whole travel along a circular path but in rotational motion the object spins on its axis.

Here, are all the statements are correct. Hence, your answer will be option [D].

In the beginning of 19th century, the invention of steam engine introduced a new source of power to run transport vehicles. Steam engines were used to pull trains on railroads or railway tracks for carrying people and goods from one place to another. Steam engines were also used to run ships in the beginning. The steam engine is called external combustion engine because the fuel or coal for making steam was burnt outside the engine.

The compass was invented in China during the Han Dynasty between the 2nd century BC and 1st century AD where it was called the “south-governor”. The Chinese first used compasses not for navigation, but for spiritual purposes. They used the magnetic devices to organize buildings and other things according to feng shui, the ancient practice of harmonizing an environment according to the “laws of Heaven.”

The scientist all over the world have adopted “International System” of units or SI units which have a uniformity in the measurement of various physical quantities like length, mass and time etc. The SI unit of measuring length is “meter”. The symbol of meter is “m”. The SI unit of measuring mass is “kilogram” (kg) and the SI unit of measuring time is “second” (s)

Here, are all the statements are correct. Hence, your answer will be option [D].

Here, all the statements are correct. Hence, your answer will be option [D].

Here, all the statements are correct. Hence, your answer will be option [D].