AI Mentor

Check Your IQ

Free Expert Demo

Try Test

Courses

Dropper NEET Course Dropper JEE Course Class - 12 NEET Course Class - 12 JEE Course Class - 11 NEET Course Class - 11 JEE Course Class - 10 Foundation NEET Course Class - 10 Foundation JEE Course Class - 10 CBSE Course Class - 9 Foundation NEET Course Class - 9 Foundation JEE Course Class -9 CBSE Course Class - 8 CBSE Course Class - 7 CBSE Course Class - 6 CBSE Course

Offline Centres

A car driver driving at a speed of ${90 kmh}^{- 1}$ applies brakes and brings the car to rest in $20 s .$ The acceleration of the car is

see full answer

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.

An Intiative by Sri Chaitanya

+ 1 m s^{- 2}

- 1.5 m s^{- 2}

- 1.25 m s^{- 2}

+ 2.5 m s^{- 2}

answer is B.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Detailed Solution

A car driver driving at a speed of

{90 kmh}^{- 1}

applies brakes and brings the car to rest in

20 s .

The acceleration of the car is

- 1.25 m s^{- 1}

.
Given data in the problem,
Initial velocity,

u = 90 km h^{- 1}

Final velocity,

v = 0

Time,

t = 20 s

Converting km

h^{- 1}

to m

s^{- 1}

\Rightarrow 90 km h^{- 1} = 90 \times \frac{5}{18} m s^{- 1}

= 25 m s^{- 1}

By using the first law of motion,

v = u + at

Where,

v

= final velocity

u

= initial velocity

a

= acceleration

t

= time

\Rightarrow 0 = 25 + a \times 20

\Rightarrow a = - 25 / 20

\Rightarrow a = - 1.25 m s^{- 1}

(Negative sign indicates that acceleration is decreasing.)
So, the acceleration of the car after

20 s

of applying brakes is

- 1.25 m s^{- 1}

Watch 3-min video & get full concept clarity

courses

No courses found

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Online Course for IIT JEE

Best Online Course for NEET

Best Online Course for CBSE

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Get Expert Academic Guidance – Connect with a Counselor Today!