Question

on finding your friend, you applied brakes on car which resulted in a change of speed from 100km/hr to 20km/hr.over a distance of 1 m. how much is the acceleration of the car​

Answer 1

Given:-

• Initial Velocity = 100km/h = 27.77m/s

• Final Velocity = 20km/h = 5.5m/s

• Distance Covered = 1m

To Find:-

• The retardation of the car.

Formulae used:-

• v² - u² = 2as

Where,

v = Final Velocity

u = Initial Velocity

a = Acceleration

s = Distance

Now,

v² - u² = 2as

(5.5)² - (27.7)² = 2 × a × 1

30.25 - 767.29 = 2a

-737.04 = 2a

a = -737.04/2

a = 368.72m/s²

Hence, The accceleration/retardation of the car is 368.72m/s²

MORE INFORMATION

• Velocity is a Vector quantity.

• The rate of the change in Velocity is known as Acceleration.

• Acceleration is a Vector quantity.

• The Slope of the Velocity time graph represent Acceleration.

Answer 2

✍ GIVEN :-

• Initial Velocity = 100km/h = 27.77m/s.

• Final Velocity = 20km/h = 5.5m/s.

• Distance = 1 metre.

✍ TO FIND :-

• Negative Acceleration/Retardation.

✍ SOLUTION :-

We know the 3rd Equation Of Motion,

v² - u² = 2as.

Put the values.

➝ 5.5² - 27.7² = 2a.

➝ 2a = -737.04

➝ a = -737.04/2.

➝ a = -368.72m/s²

Hence, Retardation = -368.72m/s².