Question

27 Find the initial velocity of a car which is stopped in 10 seconds by applying brakes The retardation due to brakes is 2.5 m/s2​

Answer 1

Intial velocity - Motion

A body is in rest or in motion till when a external force act on the body that is known as first equation of motion.

The first equation of motion deals with final velocity, initial velocity, time taken and acceleration. Or, the formula which describes the relation between acceleration and velocity is known as first equation of motion. i.e.

$\implies v = u + at$

Where, v denotes final velocity, u denotes initial velocity, a denotes acceleration and t denotes time taken.

We have been given that,

• Final velocity, v = 0m/s [Since the car is stopped]
• Time taken = 10 seconds
• Acceleration = -2.5m/s² [-ve sign indicates retardation]

With this information, we have been asked to find out the initial velocity of the car.

By using first equation of motion and substituting all the given values in it, we get:

$\implies v = u + at \\ \\ \implies 0 = u + ( - 2.5) \times 10 \\ \\ \implies 0 = u - 2.5\times 10 \\ \\ \implies 0 = u - 25 \\ \\ \implies u = 0 + 25 \\ \\ \implies \boxed{u = 25}$

Hence, the initial velocity of the car is 25m/s.

Answer 2

Answer:

Question :-

✯ Find the initial velocity of a car which is stopped in 10 seconds by applying brakes The retardation due to brakes is 2.5 m/s².

Given :-

✯ A car which is stopped in 10 seconds by applying brakes The retardation due to brakes is 2.5 m/s².

Find Out :-

✯ Find the initial velocity of a car.

Solution :-

☣ Initial velocity of a car :-

As we know that :

☆ $\red{ \boxed{\sf{v =\: u + at}}}$ ☆

We have :

☯ Final velocity, v = 0m/s

☯ Time taken = 10 seconds

☯ Acceleration = -2.5m/s²

So, according to the question or ATQ :-

➙ $\tt{0 =\: u + \{- 2.5(10)\}}$

➙ $\tt{0 =\: u + (- 25)}$

➙ $\tt{0 =\: u - 25}$

➙ $\tt{0 + 25 =\: u}$

➙ $\tt{25 =\: u}$

➙ ${\small{\bold{\purple{\underline{u =\: 25\: m/s}}}}}$

Henceforth, the initial velocity of a car is 25 m/s .

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$\qquad\qquad\underline{\textsf{\textbf{ \color{magenta}{Brainly\: Extra\: Shots :-} }}}$

Acceleration :-

• Acceleration is the process where velocity changes.
• Since, velocity is the speed and it has some direction.
• So, change in velocity is considered as acceleration.

Initial velocity :-

• Initial velocity is the velocity of the object before the effect of acceleration.

Final velocity :-

• After the effect of acceleration, velocity of the object changes.
• The new velocity gained by the object is known as final velocity.

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