Question

A bus starts to move from rest. if its velocity becomes 90km per hour after 8 s,calculate its acceleration.
Please show the process and explain it a bit too!

Answer 1

Answer:

• Acceleration of the bus is 3.125 m/s².

Explanation:

Given that:

• A bus starts to move from rest.
• Its velocity becomes 90km/h after 8 seconds.

To Find:

• Its acceleration.

As,

Acceleration is always measured in m/s².

Therefore,

We have to convert the velocity from km/h to m/s.

As we know that:

• To convert speed from km/h to m/s we have to multiply it by 5/18.

Converting 90 km/h into m/s:

$\sf{\longmapsto 90\times\dfrac{5}{18}}$

Reducing the numbers,

$\sf{\longmapsto 5\times\dfrac{5}{1}}$

Multiplying the numbers,

$\sf{\longmapsto 25}$

Hence, 90 km/h = 25 m/s

And as,

The bus started moving from rest.

Therefore,

Initial velocity of the bus will be 0 m/s.

As we know that:

$\sf{\circ \;\;a=\dfrac{v-u}{t}}$

Where,

• a = Acceleration
• v = Final velocity
• u = Initial velocity
• t = Time

Substituting the values,

$\sf{a=\dfrac{25\;m/s-0\;m/s}{8\;s}}$

Subtracting the numbers,

$\sf{\longmapsto\dfrac{25\;m/s}{8\;s}}$

$\sf{\longmapsto\dfrac{25\;m}{8\;s\times s}}$

Dividing the numbers,

$\sf{\longmapsto3.125\;m/s\times s}$

$\sf{\longmapsto3.125\;m/s^2}$

Hence, acceleration of the bus is 3.125 m/s².