Question

if a car at rest accelerate uniformly to a speed of 144km/hr in 20 sec. What is the acceleration of a car?​

Answer 1

Answer :

›»› The Acceleration of a car = 2 m/s²

Given :

• Initial velocity of a car (u) = 0 km/hr
• Final Velocity of a car (v) = 144 km/h
• Time taken by a car (t) = 20 sec

To Find :

• Acceleration of a car (a) = ?

Required Solution :

Here in this question, we have to find Acceleration of a car. So, firstly we have to convert the SI unit of Initial velocity and Final velocity of a car, to convert Initial velocity and Final velocity of car multiply the value by 5/18, after all this we will find Acceleration of a car on the basis of conditions given above.

→ Initial velocity = 0 km/hr

→ Initial velocity = 0 × 5/18

→ Initial velocity = 0 m/s

→ Final velocity = 144 × 5/18

→ Final velocity = 8 × 5

→ Final velocity = 40 m/s

Now, we have Initial velocity, Final velocity, and Time taken by a car.

• Initial velocity of a car = 0 m/s
• Final velocity of a car = 40 m/s
• Time taken by a car = 20 sec

And we need to find Acceleration of car.

From first equation of motion

→ v = u + at

→ 40 = 0 + 20 × a

→ 40 = 0 + 20a

→ 40 = 20a

→ a = 40/20

→ a = 4/2

→ a = 2 m/s²

║Hence, the Acceleration of a car is 2 m/s².║

Additional Information :

★ First equation of motion :

⪼ v = u + at

Where,

• v is the Final velocity in m/s.
• u is the Initial velocity in m/s.
• a is the Acceleration in m/s².
• t is the Time taken in second.

★ Second equation of motion :

⪼ s = ut + ½ at²

Where,

• s is the Distance travelled in m.
• u is the Initial velocity in m/s.
• a is the Acceleration in m/s².

★ Third equation of motion :

⪼ v² = u² + 2as

Where,

• v is the Final velocity in m/s.
• u is the Initial velocity in m/s.
• a is the Acceleration in m/s².
• s is the Distance travelled in m.