Question

A car brakes from 60 km/h to a full stop in 4 seconds. Find the acceleration of the car during this time interval in m/s2

Answer 1

Answer:

-4.16 m/s^2

Explanation:

According to the given question,

u = initial velocity = 60 km/h = 60×1000/3600 = 16.67 m/s

v = final velocity = 0 m/s

t = 4 sec

a = acceleration

And we asked to find the acceleration of car in the given interval.

We know,

• v = u+at

Putting the values we get,

• 0 = 16.67 + a × 4

• 4a = -16.67

• a = - 16.67 / 4

• a = - 4.16 m/s^2

Thus acceleration of the car is - 4.16 m/s^2 or we can say deceleration of the car is 4.16 m/s^2.

Answer 2

Here we have some information :-

Initial velocity = 60 km/h

${\implies 60\times\dfrac{1000}{3600}}$

= 16.67 m/s

Final velocity = 0 m/s

Time = 4 sec

Acceleration = To find

Using first equation of motion

v = u + at

⇒ 0 = 16.67 + a × 4

⇒ 4a = -16.67

${\implies a = \dfrac{-16.67}{4}}$

${\implies a = -4.16 m/s^{2}}$

Here (-) this symbol recognize deceleration