Question

The brakes applied to a car produce an acceleration of $6{\text{m/s}}^2$ in the opposite direction to the motion. If the car takes $2\text{s}$ to stop after the application of brakes, calculate the distance it travels during this time.

• A. $15\text{m}$
• B. $16\text{m}$
• C. $20\text{m}$
• D. $12\text{m}$

Answer 1

Step 1, Given data

Acceleration a = $-6{\text{m/s}}^2$

Time t = 2 sec

Step 2, Finding the distance traveled

We know,

From first equation of motion,

$v=u+at$

Putting all the vlaues

$0=u+(-6)\times 2$
Initial velocity $u=12\text{m/s}$

Now,
Distance traveled is,

From the equation of motion

$s=ut+\frac{1}{2}a{t}^2$

Putting all the values

$=12\times 2+\frac{1}{2}\times (-6)\times (2{)}^2$

$=24-12=12\text{m}$

Hence the distance traveled is 12 m

The correct option is D $12\text{m}$