Question

if a bus travelling at 20 m/s is subjected to a steady deceleration of 5 m/s^2 how long will it take to come to rest​

Answer 1

Given :

• Initial Velocity, u = 20 m/s

• Final Velocity, v = 0 m/s

• Acceleration, a = -5m/s² (minus due to deceleration)

To find :

• Time - ???

Solution :

✞ Initial Velocity = 20 m/s

✞ Final Velocity = 0 m/s (Since bus is coming to rest)

✞ Acceleration = -5 m/s (Since it is decelerating)

Using the first equation of motion, we get:

Equation:

$\underline{\boxed{\frak{\pm{\green{v = u + at}}}}}\:\red{\bigstar}</p><p>$

Substituting the values,

$: \implies \bf 0 = 20 - 5(t)</p><p></p><p>$

$: \implies \bf 5t = 20</p><p></p><p>$

$</p><p></p><p> : \implies \bf t = \frac{20}{5} </p><p></p><p>$

$: \implies \bf t = 4$

Hence it would take 4 seconds for the bus to come to rest.

Answer 2

Explanation:

given :

• if a bus travelling at 20 m/s is subjected to a steady deceleration of 5 m/s^2 how long will it take to come to rest

to find :

• how long will it take to come to rest

solution :

• We have to find the time taken to reach the given final velocity.

• We have:

• Initial velocity (u) = 20 m/s

• Final velocity (v) = 0 m/s

• Acceleration for the entire journey (a) =

• -5 ms².

• Let the time taken be (t).

• We can calculate the time taken using

• the first equation of motion.

• `t = (v-u)/a`

• Time taken by the bus to come to rest:

• = (0-20)/-5

• = 4s