Question

when a car travel at a speed of 60km/he applies brake it comes to rest in 15s then the retardation of the car is​

Answer 1

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Given

• a car travel at a speed of 60 km/h applies brake it comes to rest in 15 s

To Find

• Retardation of the car

Concept Used

• Retardation and acceleration are both same but opposite in direction

Solution

Initial velocity , u = 60 km/h = 16.67 m/s²

Final velocity , v = 0 m/s

Since , finally comes to rest

Time , t = 15 s

Acceleration , a = ? m/s²

Apply 1st equation of motion ,

⇒ v = u + at

⇒ (0) = (16.67) + a(15)

⇒ 15a = -16.67

⇒ a = -1.12 m/s² 

Answer 2

Step-by-step explanation:

QUESTION -

when a car travel at a speed of 60km/he applies brake it comes to rest in 15s then the retardation of the car is

FORMULA USED HERE :

a = ( v + u ) / 2 × t

V = u + at

Method to do -

Just by converting the initial velocity in meter per second and apply the formula to find out the actual result .

Additional -

Retardation - It refer to the negative form of acceleration means when the moving object or body covers any distance in opposite direction from the target .

SOLUTION -

using formula ,

v= u + at

Then,

initial velocity = 60 km/hrs

=( 60×1000) / 60 × 60

= 16.67m/s

final velocity = 0m/s

time taken = 15 seconds

So ,

v = u + at

0 = 16.67 + 15a

a= - 16.67 / 15 m/s²

a = - 1.11m/s²