Question

A body is moving with uniform acceleration has a velocity 20 m/s. After travelling for 50 sec, its velocity became 40 m/s. Calculate the displacement covered by it during this time.​

Answer 1

Given:-

• Initial velocity ,u = 20m/s
• Final velocity ,v = 40m/s
• Time taken ,t = 50s

To Find:-

• Displacement of the body ,s

Solution:-

⠀⠀⠀⠀⠀⠀⠀⠀⠀According to the Question

Firstly we calculate the acceleration of the body . Using 1st equation of motion.

• v = u+at

where,

• v is the final velocity
• a is the acceleration
• u is the initial velocity
• t is the time taken

Substitute the value we get

$:\implies$ 40 = 20 + a×50

$:\implies$ 40-20 = 50a

$:\implies$ 50a = 20

$:\implies$ a = 20/50

$:\implies$ a = 2/5

$:\implies$ a = 0.4 m/s²

So, the acceleration of the body is 0.4m/s²

Now, calculating the displacement of the body. Using 3rd equation of motion

• v² = u² + 2as

substitute the value we get

$:\implies$ 40² = 20² + 2(0.4) × s

$:\implies$ 1600 = 400 + 0.8×s

$:\implies$ 1600-400 = 0.8s

$:\implies$ 1200 = 0.8s

$:\implies$ s = 1200/0.8

$:\implies$ s = 1500 m

• Hence, the distance covered by the body is 1500metres or 1.5 kilometres.

Answer 2

Given :-

A  body is moving with uniform acceleration has a velocity 20 m/s. After travelling for 50 sec, its velocity became 40 m/s.

To Find :-

Displacement

Solution :-

Finding acceleration

a = v - u/t

a = 40 - 20/50

a = 20/50

a = 2/5

Now

v² - u² = 2as

40² - 20² = 2(2/5)(s)

1600 - 400 = 4/5s

1200 = 4/5s

1200 × 5 = 4s

60,000 = 4s

60,000/4 = s

15,000 = s