Question

A body is moving along a straight line at 20 m/s undergoes an acceleration of 4 ms-2 .After 2 seconds the speed in ms-1 will be

Answer 1

GIVEN :-

• Initial velocity = 20 m/s.
• Acceleration = 4 m/s².
• Time = 2 seconds.

TO FIND :-

• Final velocy.

SOLUTION :-

★ Here we can solve this question by two methods.

[1]

✭ a = (v - u)/t

• a → Acceleration.
• v → Final velocity.
• t → Time taken.
• u → Final velocity.

➳ 4 = (v - 20)/2

➳ 4 × 2 = v - 20

➳ 8 = v - 20

➳ v = 20 + 8

➳ v = 28 m/s.

[2]

✭ v = u + at

• a → Acceleration.
• v → Final velocity.
• t → Time taken.
• u → Final velocity.

➳ v = 20 + 4 × 2

➳ v = 24 + 8

➳ v = 28 m/s.

Hence the speed after 2 seconds will be 28 m/s.