Question

If a bus travelling at 20 m/s is subjected to a steady deceleration of 5,m/ s ^2 . how will it take to come to rest

please tell me​

Answer 1

Answer:

4 sec and 40 m

Explanation:

According to the given question,

u = initial velocity = 20 m/s

-a = deceleration = 5 m/s^2

v = final velocity = 0 m/s

t = time = ? and displacement = ?

And we are asked to find the time and displacement. (As in question it's asked how")

Here displacement is equal to distance as it's a linear motion.

We know,

• v = u+at

Putting the values we get

• 0 = 20 - 5t

• t = 20/5

• t = 4 sec

Again,

• s = ut+1/2 at^2

Putting the values we get,

• s = 20×4 - 1/2 ×5 ×16

• s = 80 - 40

• s = 40 m

Therefore, bus will take 4 sec and 40 m to come to rest.

Answer 2

Answer: 4  second.

Explanation:

Given,

Bus is travelling with a speed of 20 m/s. It means it is its initial Velocity. Also, bus has deceleration. It means bus will stop after sometime. It means its final velocity is zero. Let that time be t.

Initial Velocity (u) = 20 m/s

Final Velocity (v) = 0

Deceleration (a) = -5

Time (t) = ?

Now,

Using first equation of motion;

v = u + at

0 = 20 + (-5)*t

0 = 20 - 5t

5t = 20

t = 20/5

t = 4 second

Hence, It will take 4 seconds to  come to rest.