Question

If 50 m is the distance at which a car can be stopped when initially it was moving with speed 10 m/sec, then on making the speed of the car50 m/s, what is the distance at which a car can be stopped?​

Answer 1

DISTANCE REQUIRED IS 1250 metres.

Given:

• Distance to stop when moving with 10 m/s is 50 metres.

To find:

Distance to stop when moving with 50 m/s ?

Calculation:

• We will assume the fact that in both cases the retardation offered by the brakes of the car will be equal.

Case 1 :

• Applying EQUATIONS OF KINEMATICS:

${v}^{2} = {u}^{2} + 2as$

$\implies \: 0 = {10}^{2} + 2(a)(50)$

$\implies \:100a = - 100$

$\implies \:a = - 1 \: m {s}^{ - 2}$

Now, Case 2:

• Again applying EQUATIONS OF KINEMATICS:

${v}^{2} = {u}^{2} + 2ad$

$\implies 0 = {50}^{2} + 2( - 1)d$

$\implies 2d = 2500$

$\implies d = 1250 \: m$

So, distance required to stop is 1250 metres.

Answer 2

Answer:

The car stops at 1250 m when it starts with initial speed 50 m/s.

Explanation:

we will be using equation of motion.

Given :   car moves with initial speed  (u) = 10m/s      

       stops at distance (s) = 50 m        

 when speed  initial speed is = 50 m/s   we need to find distance at which it stops.  

Step 1 :  using  third equation of motion      

     v² - u² = 2as    

     0 - 10² = 2a (50)    

    -100 = 100a      

    a = -1 m/s²

acceleration will be same.

Step 2:   now to calculate distance it will stop if it starts with initial speed 50 m/s  

 v² - u² = 2as  

 0- 50² = 2(-1)s  

 2500 = -2s

  s = 1250 m