Question

A car is moving with a speed of 40 m/s. On applying brake, it comes to rest at 20 s. What is the distance between the distance covered by the car before it stops?

Answer 1

To find the distance covered by the car before it comes to a stop, we can use the equation of motion:

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

Where:

• $v$ is the final velocity (0 m/s, as the car comes to rest)
• $u$ is the initial velocity (40 m/s)
• $a$ is the acceleration (unknown)
• $s$ is the distance covered (unknown)

Given that $v=0$, $u=40\text{m/s}$, and the time $t=20\text{s}$, we can solve for $s$.

First, let's rearrange the equation:

$0=(40{)}^2+2as$

Simplifying further:

$0=1600+2as$

Since the car comes to rest, its final velocity is 0 m/s. We can now solve for $s$:

$-1600=2as$

Dividing both sides by 2a:

$-800=as$

Now, substituting the time <span