Teachoo Questions

Class 9
Chapter 8 Class 9 - Motion

## Find Displacement and Acceleration from Time 0-2 seconds, 2-10 secs, 10-12 seconds, 12-16 seconds. Also tell the type of motion in all the regions. And find the total displacement

Letβs mark the points and their coordinates

Motion in region OA = Uniformly accelerated

Motion in region AB = Uniformly motion (No acceleration)

Motion in region BC = Uniformly retarded

Motion in region CD = Uniformly motion (No acceleration)

Total displacement

Β  Β = Displacement in OA + Displacement in AB

Β  Β  Β + Displacement in BC + Displacement in CD

Β  = 8 + 64 + 12 + 16

Β  = 100 m

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### Transcript

In 2 β 10 seconds (Region AB) Acceleration = Slope of AB = (π¦_2 β π¦_1)/(π₯_2 β π₯_1 ) = (8 β 8)/(2 β 0) = 0/2 = 0 m/s2 Displacement = Area under v β t graph = Area of rectangle ABQP = Length Γ Breadth = AP Γ AB = 8 Γ 8 = 64 m In 10 β 12 seconds (Region BC) Acceleration = Slope of BC = (π¦_2 β π¦_1)/(π₯_2 β π₯_1 ) = (4 β 8)/(12 β 10) = (β4)/2 = β2 m/s2 Acceleration = Slope of BC = (π¦_2 β π¦_1)/(π₯_2 β π₯_1 ) = (4 β 8)/(12 β 10) = (β4)/2 = β2 m/s2 In 12 β 16 seconds (Region CD) Acceleration = Slope of OA = (π¦_2 β π¦_1)/(π₯_2 β π₯_1 ) = (4 β 4)/(16 β12) = 0/4 = 0 m/s2 Displacement = Area of rectangle CDSR = Length Γ Breadth = CD Γ CR = 4 Γ 4 = 16 m