Question

A body, moving with a certain initial velocity and acceleration of 4 ms−2 , has a displacement of 50 m in 10 s.The final velocity attained by it is


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Answer 1

Given:

• Body is moving with certain initial velocity let u

• Acceleration of body, a = 4 ms⁻²
• displacement of body, s = 50 m
• time taken, t = 10 s

To find:

• Final velocity attained by body, v =?

Formulae required:

• First equation of motion

     v = u + a t

• Second equation of motion

     s = u t + 1/2 a t²

[ Where v is final velocity, u is initial velocity, s is distance covered, a is acceleration, t is time taken ]

Solution:

Using second equation of motion

→ s = u t + 1/2 a t²

→ 50 = u ( 10 ) + 1/2 ( 4 ) ( 10 )²

→ 50 = 10 u + 200

→ 10 u = 50 - 200

→ u = -150/10

→ u = -15 m/s

Therefore,

• Initial velocity of body is -15 m/s.

Now, Using first equation of motion

→ v = u + a t

→ v = ( -15 ) + ( 4 ) ( 10 )

→ v = -15 + 40

→ v = 25 m/s

Hence,

• Final velocity attained by body would be 25 m/s.