A body starts with an initial velocity of 10 m s and acceleration 5 m s 2 . Find the distance covered by it in 5 s .

Given: u = 10 m s ; a = 5 m s 2 ; t = 5 s ; s = ? Distance travelled, s = u t + 1 2 a t 2 = 10 × 5 + 1 2 ( 5 ) ( 5 ) 2 = 50 + 62 . 5 = 112 . 5 m

A vehicle is accelerating on a straight road. Its velocity at any instant is 30 k m h , after 2 s , it is 33 . 6 k m h and after further 2 s , it is 37 . 2 k m h . Find the acceleration of vehicle in m s 2 . Is the acceleration uniform?

We know that acceleration = Rate of change of velocity Velocity in the first 2 s is 33 . 6 k m h &there4; Acceleration 33 . 6 - 30 2 = 3 . 6 2 = 1 . 8 k m h 2 Converting k m h 2 to m s 2 1 . 8 × 1000 60 × 60 = 0 . 5 m s 2 Further velocity after 2 s is 37 . 2 k m h &there4; Acceleration = 37 . 2 - 33 . 6 2 = 3 . 6 2 = 1 . 8 k m h 2 Converting k m h 2 to m s 2 1 . 8 × 1000 60 × 60 = 0 . 5 m s 2 Comparing acceleration from both instances it can be said that the acceleration is uniform.

E M B I B E

Concise Physics I.C.S.E Part I For Class 9>Chapter 2 - Motion in One Dimension>EXERCISE–2(B)>Q 8

MEDIUM

9th ICSE

IMPORTANT

Earn 100

The figure shows velocity-time graph for the motion of a body. Use it to find the displacement of the body at $t = 1 s, 2 s, 3 s$ and $4 s$ , then draw displacement-time graph for it on figure (b).

Important Questions on Motion in One Dimension

MEDIUM

9th ICSE

IMPORTANT

Concise Physics I.C.S.E Part I For Class 9>Chapter 2 - Motion in One Dimension>EXERCISE–2(B)>Q 11

A ball moves on a smooth floor in a straight line with a uniform velocity

10 m s^{- 1}

for

6 s

. At

t = 6 s

, the ball hits a ball and come back along the same line to the starting point with same speed. Draw the velocity-time graph and use it to find the total distance travelled by the ball and its displacement.