Motion and Measurement of Distances

Motion and Measurement of Distances : Motion and Measurement of Distances

What are the means of Transportation? : What are the means of Transportation? Trains Buses Ships Aeroplanes Bicycles Motor-Cycles

How do people know how far they have travelled? : How do people know how far they have travelled? This is done by a term called Measurement Measurement means the comparison of an unknown quantity with some known quantity The known fixed quantity is called a Unit The result of a measurement is expressed in two parts. One part is a number. The other part is the unit of the measurement.

Example : Example The length of the hand measures 9 cm. 9 cm The number 9 forms one part (Unknown Quantity) Cm is the Unit (Fixed Quantity)

Different Units of Measurement : Different Units of Measurement For the sake of uniformity, scientists all over the world have accepted a set of standard units of measurement known as the International System of Units (SI units) The SI unit of length is a Meter Each metre (m) is divided into 100 equal divisions, called centimetre (cm) Each centimetre has ten equal divisions, called millimetre (mm) For measuring large distances, we use a larger unit of length, called kilometre (km)

Slide 6 : 1 m = 100 cm 1 cm = 10 mm 1 km = 1000 m

Instruments used for measuring length : Instruments used for measuring length Have you ever observed A tailor uses a measuring tape to take measurements Whereas a carpenter uses a different measuring tape Why are these instruments different? For measuring the length of an object, we must choose a suitable device in order to get accurate results

You may have observed the motion of a vehicle on the road or a bird flying : You may have observed the motion of a vehicle on the road or a bird flying Motion is defined as some kind of a change in the position of an object with time There are three kinds of motion Rectilinear Motion Circular Motion Periodic Motion

Rectilinear Motion : Rectilinear Motion Motion in a straight line is called Rectilinear motion Car on a straight road March-past of soldiers in a parade Water falling from a height

Circular Motion : Circular Motion In a circular motion an object moves such that its distance from a fixed point remains the same Blades of a fan moving Giant Wheel moving Movement of the planets around the sun

Periodic Motion : Periodic Motion Motion that repeats itself after a period of time, is called Periodic motion Motion of a Pendulum Motion of a child on the swing Branch of a tree moving to and fro

Can an object undergo more than one motion at the same time? : Can an object undergo more than one motion at the same time? A ball rolling on ground shows both rotational (circular) as well as rectilinear (moving forward) motion A Sewing Machine remains at the same location while its wheel moves with a circular motion. It also has a needle that moves up and down undergoing a periodic motion

Slide 13 : The change in the position of an object can be determined through distance. Measurements which we have discussed earlier. This allows us to know how fast or slow a motion is.

Thank You : Thank You