Question

Proper mind map of chapter motion class 9th , all the information and defination

Answer 1

The following is the mind map of the Chapter- Motion from class 9th to facilitate easier understanding of the same.

• Motion- The change in position of an object with respect to a reference point, with time.

• Motion can be in a straight line or along a curved path. 2 terms- distance and displacement- are used to measure the overall motion of the body.

⇒ Distance: Complete length of the path between two points (vector)

⇒ Displacement: Direct length between the initial and final position (scalar)

• Motion can be uniform or non-uniform

⇒ Uniform motion: equal distances travelled in equal intervals of time

⇒ Non-uniform motion: unequal distances travelled in equal intervals of time

• Rate of motion can be measured in two ways- speed and velocity

⇒ Speed: distance travelled in unit time. SI unit is m/s (scalar)

Average speed = $\frac{Total-distance- travelled}{Total- time- taken}$

⇒ Velocity: speed of an object moving in a definite direction. (vector)

Average velocity = $\frac{initialvelocity+finalvelocity}{2}$

• Acceleration: rate of change of velocity = $\frac{change-in -velocity}{time -taken}$

⇒ a = (v-u)/t

⇒ SI unit is m/s²

⇒ Uniform acceleration: velocity changes by equal amounts in equal intervals of time

⇒ Non-uniform acceleration: velocity changes by unequal amounts in equal intervals of time

• Motion can be represented in distance-time graphs and velocity-time graphs. Following equations of motion can be deduced from graphs-

⇒ v = u + at

⇒ s = ut + 1/2 at²

⇒ 2as = v² - u²

• Uniform circular motion- when an object moves in a circular path with uniform speed, it is an example of accelerated motion

⇒ if radius = r and time taken = t, then velocity in U.C.M. = 2r/t

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