Question

A body, moving with uniform acceleration, has initial velocity 45 km/hr ; and
acceleration 20 cm/s. Find its velocity after 25 seconds.​

Answer 1

Given:-

• Initial velocity (u) = 45km/h = 45×5/18 = 225/18m/s

• Time taken (t) = 25s

• Acceleration (a) = 20cm/s = 2/10m/s

To Find:-

• Final velocity (v)

Solution:-

By using 1st equation of motion

⟹ v = u +at

Substitute the value we get

→ v = 225/18 + 2/10 × 25

→ v = 225/18 + 5

→ v = 12.5+5

→ v = 17.5m/s

∴ The Final velocity of the body is 17.5m/s

Answer 2

Explanation :-

✔ Given :-

• Initial velocity (u) = 45km/hr = 45 × 5/18 = 45×5/18 = 225/18 = 12.5m/s.

• Acceleration (a) = 20cm/s² = 20/100 = 0.2m/s².

• Time (t) = 25sec.

✔ To Find :-

• The final velocity (v) of the body.

✔ Solution :-

Applying 1st equation of motion,

v = u + at

[ Substituting the values ]

=> v = 12.5 + 0.2×25

=> v = 12.5 + 5

=> v = 17.5m/s

✔ Hence,

• The final velocity of the body is 17.5m/s.

✔ Verification :-

v = u + at

[ Putting values ]

=> 17.5 = 12.5 + 0.2 × 25

=> 17.5 = 12.5 + 5

=> 17.5 = 17.5

✔ Hence Verified.