Question

A car moving with an initial velocity of 4 m/s is subjected to a uniform acceleration of
2 m/s2 for 20 seconds. Find its final velocity.
(A) 23 m/s
(B) 40 m/s
(C)44 m/s
(D) 48 m/s
above question find distance covered by car.

​

Answer 1

Let the initial velocity be u and acceleration be a.

Case 1 :

Distance covered S=20 m

Time taken t=1 s

Using S=ut+

2

1

​

at

2

Or 20=u(1)+

2

1

​

a(1)

2

⟹ 20=u+

2

a

​

We get u=20−

2

a

​

Case 2 :

Total distance covered S=20+30=50 m

Total time taken t=1+1=2s

So, 50=u(2)+

2

1

​

a(2)

2

or 50=2u+2a

Or 50=2(20−

2

a

​

)+2a

Or 50=40−a+2a

⟹ a=10 m/s

2

Hi there this answer is from my textbook.

Answer 2

Explanation:

acceleration (a) = 2m/s² u=4m/s t=20 seconds

a = v-u

t

by putting values

2=v-4

20

2x20=v-4

40=v-4

40+4=v

44=v

final velocity=44m/s (c)

I hope this will help you

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