Question

find the initial velocity of a car which is stopped in 10 seconds by applying brakes the retardation due to brakes is 2.5m per second​

Answer 1

Aɴꜱᴡᴇʀ

☞ Initial velocity of the body is 25 m/s

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Gɪᴠᴇɴ

➳ Acceleration (a) = (-2.5 m/s²)

➳ Time (t)= 10 seconds

➳ Final velocity (v) = 0 m/s

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Tᴏ ꜰɪɴᴅ

➤ Initial velocity (u) ?

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Sᴛᴇᴘꜱ

So here as we have the accelerataion,the time taken and the final velocity.

✴ The formula that connects them is,

$\large \underline{ \boxed{ \sf{v = u + at}}}$

Substituting the given values,

$\large\tt \leadsto{}0 = u + ( - 2.5)(10) \\ \\ \large \tt \leadsto{} \cancel- \: u = \cancel - \: 25 \\ \\ \large \tt \pink{ \leadsto{}u = 25m/s}$

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Answer 2

Given:-

• Final velocity,v= 0m/s
• Time taken to stop ,t = 10s
• Retardation ,a = -2.5m/s²

To Find:-

• Initial velocity ,u ?

Solution:-

According to the Question

It is given that a car which is stopped in 10 second by applying breaks and the reterdiation due to Break is 2.5m/s².

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

Putting the value we get

→ 0 = u + (-2.5) × 10

→ -u = -25

→ u = 25m/s

Hence, the initial velocity of the car is 25m/s²

$\: \: \: \: \: \:$$\huge\fbox{→25m/s²}$