Question

The body with an initial velocity of 18 km/hr.its acceleration is 9 m/s² over a distance of 200m . find the final velocity of the body in m/ sec
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Answer 1

Given :

Initial velocity, u = 18 km/h

Acceleration, a = 9 m/s

Distance covered, s = 200 m

To Find :

Final velocity of the body

Solution :

First of all we have to convert km/hr to m/s

1km/hr = 5/18 m/s

18km/hr = 18 × 5/18 = 5 m/s

As we are provided with initial Velocity, accerlation and distance we can use 3rd equation of motion i.e.,

${\leadsto {\bf {v^2-u^2=2as}}}$

${\leadsto{\sf {v^2-(5)^2=2(9)(200)}}}$

${\leadsto {\sf {v^2-25=3600}}}$

${\leadsto{\sf {v^2=3600+25}}}$

${\leadsto{\sf {v^2=3625}}}$

${\leadsto { \boxed{\bf{v=60.2\ m/s}}}}$

thus, the final velocity of the body is 60.2m/s.

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#sanvi….

Answer 2

Given :

• Initial velocity (u) = 18 km/h = 5 m/s
• Acceleration (a) = 9 m/s²
• Distance (s) = 200 m

To find :

• Final velocity

According to the question,

By using Newtons third equation of motion,

→ v² = u² + 2as

Where,

• v = Final velocity
• u = Initial velocity
• a = Acceleration
• s = Distance

→ Substituting the values,

→ v² = (5)² + 2 × 9 × 200

→ v² = 25 + 3600

→ v² = 3625

→ v² = 60.2

So,the final velocity is 60.2 m/s.

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More formula :

Newton's first equation of motion :

• v = u + at

Newton's second equation of motion :

• s = ut + ½ at²

Newton's third equation of motion :

• v² = u² + 2as