Question

A car is moving with a speed of 10 m/s and with an acceleration of 7 m/s2 . how long will it take to reach to a speed of 80m/s

Answer 1

Given

• Initial Velocity = 10 m/s
• Acceleration = 7 m/s²
• Final Velocity = 80 m/s

To Find

• Time taken to reach that velocity

Solution

● v = u + at [First Equation of Motion]

✭ Time Taken to reach the velocity :

→ v = u + at

→ 80 = 10 + (7 × t)

→ 80 - 10 = 7t

→ 70 = 7t

→ 70/7 = t

→ Time = 10 sec

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Another Method

• Acceleration = (v-u)/t

→ 7 = (80-10)/t

→ 7 = 70/t

→ t = 70/7

→ Time = 10 sec

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Know More

• s = ut + ½at² [Second Equation of Motion]
• v²-u² = 2as [Third Equation of Motion]
• Most of the questions that ask us time, are related on these three Equations of motion

Answer 2

Given:-

¤ A car is moving with a speed of 10 m/s and with an acceleration of 7 m/s²

To Find:-

¤ how long will it take to reach to a speed of 80m/s?

Solution:-

¤ To Find the time taken:-

¤ Using formula,

$\LARGE\star{ \underline{ \boxed{ \frak{\pink{v = u + a t}}}}}$

¤ Substitute the value given in the formula..

$\star{ \underline{ \boxed{ \frak{ \pink{80 = 10 + 7 \times t}}}}}$

$\star{ \underline{ \boxed{ \frak{ \pink{80 - 10 = 7 t}}}}}$

$\star{ \underline{ \boxed{ \frak{ \pink{70 = 7 t}}}}}$

$\star{ \underline{ \boxed{ \frak{ \pink{ t = 10}}}}}$

¤Hence, the time taken to reach to a speed of 80 m/s is 10 second..