NCERT Solutions Class 6th Science Chapter – 7 Motion and Measurement of Distances Notes In this Chapter We Will read about measurement, circular motion, types of motion, distance, motion and measurement, SI unit, distance called in physics and basic unit of measurement etc. and More much. you have provided easy notes which use in your study make progress in education.
NCERT Solutions Class 6th Science Chapter – 7 Motion and Measurement of Distances
Chapter – 7
Measurement of Distances
Notes
A great change in the modes of transport was made
By the invention of the wheel.
By the invention of the steam engine.
Non-standard measures – The lengths of steps, arms, hands, or fingers of different people are different, therefore the distance measured with their help is not always reliable. These methods are, therefore, called non-standard measures.
Standard measures – Measures that are the same all over the world are known as standard measures.
In October 1960, the 12th general conference on weight and measures adopted the International system of units.
The System International Units” is the set of units to maintain uniformity all over the world.
Metre
It is the standard unit of length. The symbol of the metre is m.
Each metre (m) is divided into 100 equal divisions, called centimetres (cm).
Each centimetre has ten equal divisions, called millimeter’s (mm). Thus
1 m = 100 cm
1 cm = 10 mm
For measuring large distances, the metre is not a convenient unit. We define a larger unit of length. It is called kilometre (km).
1 km = 1000 m.
Simple multiples of units – Units that are used for the measurement of larger distances are the multiples of SI units. For example deca, hecto, kilo.
1 decimeter = 10 m
1 hectometre = 100 m
1 kilometre = 1000 m
Sub-multiples of units– Units used for measuring smaller distances are the sub-multiples of SI units. For example, milli, centi, deci.
1 m = 10 decimetre
1 m = 100 centimetre
1 m = 1000 millimetre.
Making measurement of a length – In making a measurement of the length of an object, we should follow the following procedure – Place the scale in contact with the object along its length as shown in Fig.
Measurement with a scale with broken ends
Avoid taking measurements from zero mark.
Use any other full mark of the scale, say 1.0 cm.
Subtract the reading of this mark from the reading at the other end. For example, in Fig. 10.3 (6).
The reading at starting mark is 1.0 cm and at the other end, it is 6.5 cm.
Therefore, the length of the object is (6.5 – 1.0) cm = 5.5 cm.
The correct position of the eye is also important for making measurements.
Your eye must be exactly above the point where the measurement is to be taken as shown in Fig. 10.4. Position ‘A’ is the correct position of the eye. Note that from position A’.
The reading is 1.0 cm. From positions ‘B’ and ‘C’, the readings may be different.
Least count – A scale is marked in centimetres and millimeters. With the scales of this kind we can measure correctly up to one millimetre, that is one-tenth of a centimetre. This is called the least count of a (15 cm) scale.
Measuring the length of a curved line – We cannot measure the length of a curved line directly by using a metre scale. We can use a thread or divider to measure the length of a curved line.
Motion – It is a state of objects in which they are moving, that is, they are changing their place with the changing time.
Rest – All the stationary objects which are not in motion, that is, do not change their place with time are said to be at rest.
Rectilinear motion – When the objects change their position with time along a straight line, this type of motion is called rectilinear motion.
Circular motion –When a body moves in a circular path, its motion is known as circular motion Examples:
The motion of stone tied in a thread and whirled.
The motion of a blade of an electric fan.
The motion of the second’s hand in a clock.
In a circular motion, the object remains at the same distance from a fixed point.
Rotational motion – Motion in which a whole body moves about an axis is called a rotational motion. Example: motion of a top.
Periodic motion – Motion in which an object repeats its motion after a fixed interval of time is called periodic motion. Examples:
Oscillations of a pendulum.
Motion of a swing.
Combination of two or more types of motions – In some situations, the motion of an object may be a combination of two or more of the above-mentioned types of motion. Examples-
The motion of a ball on the ground. Here, the ball is rotating about an axis but the axis itself is moving along a straight line. Thus, the ball executes a rectilinear motion as well as a rotational motion.
The motion of the earth executes rotations on its axis and also revolves around the sun.
Unit of measurements
It involves the comparison of an unknown quantity with some known quantity of the same kind.
This known fixed quantity is called a unit.
The result of the measurement is expressed in two parts. One part is a number; the other part is the unit of measurement.
Keywords
Circular motion – When a body moves in a circular path, its motion is known as circular motion.
Distance – Measurement of the gap between two points in certain units is called distance.
Measurement – Measurement means the comparison of an unknown quantity with some known quantity.
Motion – It is a state of objects in which they are moving that is, they are changing their place with time.
Periodic motion – Motion in which an object repeats its motion after a fixed interval of time is called periodic motion.
Rectilinear motion – When the objects change their position with time along a straight line, this type of motion is called rectilinear motion.
SI units – In October 1960 the 12th general conference on weight and measures adopted
The International System of units to maintain uniformity
All over the world. This system of units is called SI units.
Units of measurement – Measurement means the comparison of an unknown quantity with some known quantity. This known fixed quantity is called a unit of measurement.
1. What is distance measurement?
Ans – In the metric system of measurement, the most common units of distance are millimeters, centimeters, meters, and kilometers.
2. What are types of motion?
Ans – A motion is when the position of an object changes over a certain period of time. There can be various types of motion including oscillatory, rotational, transactional, uniform, non-uniform, periodic, circular and linear.
3. What is the SI unit of distance?
Ans – SI unit of distance is a metre according to the International System of Units. Interestingly, using this as the base unit and some equations, many other derived units or quantities are formed like volume, area, acceleration, and speed.
4. What is called motion?
Ans – A property in which a body changes its position with respect to time is known as motion.
Ans – Different types of force are contact forces and non- forces. Some examples of force are Nuclear force, gravitational force, Frictional force, magnetic force, electrostatic force, spring force and so on.
7. What are the 2 main types of force?
Ans – there are two types of forces: 1. Non-contact forces. 2. Contact forces.
NCERT Solutions Class 6th Science All Chapters Notes
