Question

A bus moving with the velocity of 90 km / he If mass of the bus is 250 kg how much regarding force is applied to stop the bus in 10 second ? Also calculate the distance travelled by the bus at that time.

Answer 1

Given :

• Initial velocity (u) = 90 km/h = 25 m/s
• Final velocity (v) = 0 m/s
• Time interval (t) = 10 s
• Mass of bus (m) = 250 kg

To Find :

• Retarding Force applied
• Distance travelled by bus

Solution :

First we've to find acceleration with which the bus is moving :

$\implies \sf{v \: = \: u \: + \: at} \\ \\ \implies \sf{0 \: = \: 25 \: + \: 10a} \\ \\ \implies \sf{10a \: = \: -25} \\ \\ \implies \sf{a \: = \: \dfrac{-25}{10}} \\ \\ \implies \sf{a \: = \: -2.5}$

$\therefore$ Acceleration of bus is -2.5 m/s²

Negative sign indicates that acceleration is applied in opposite direction of motion

________________________________

Retarding force applied is :

$\implies \sf{F \: = \: ma} \\ \\ \implies \sf{F \: = \: -2.5 \: \times \: 250} \\ \\ \implies \sf{F \: = \: -625}$

$\therefore$ Retarding force applied is -625 N

Negative sign indicates force is applied on opposite direction of motion

____________________________

Distance travelled by bus is :

$\implies \sf{v^2 \: - \: u^2 \: = \: 2as} \\ \\ \implies \sf{0^2 \: - \: 25^2 \: = \: -5s} \\ \\ \implies \sf{-625 \: = \: -5s} \\ \\ \implies \sf{s \: = \: \dfrac{-625}{-5}} \\ \\ \implies \sf{s \: = \: 125 }$

$\therefore$ Distance travelled by bus is 125 m

Answer 2

Answer:

Given:

• A bus moving with the velocity of 90 km / he If mass of the bus is 250 kg.

Find:

• Find how much regarding force is applied to stop the bus in 10 second.
• Calculate the distance travelled by the bus at that time.

According to this question, there are two parts or two cases:

Know terms:

1. Initial velocity = (u)
2. Final velocity = (v)
3. Acceleration = (a)
4. Time = (t)
5. Mass = (m)
6. Force = (f)

Calculations:

Case-1 [Finding the Acceleration]

Formula:

=> v = u + at

Step-by-step calculations:

=> 0 = 25 + 10 a

=> 10 a = -25

=> a = -25/10

=> a = -2.5

Hence, -2.5 m/s is the acceleration.

Case-2 [Finding retarding force]

Formula:

=> f = ma

Step-by-step calculations:

=> f = -2.5 × 250

=> f = -625

Hence, -625 is the retarding force applied.

Note:

• For both the calculations above, note that (-ve) sign indicates that acceleration and force is applied opposite direction of motion.

Finding the distance travelled by the bus:

Fomula:

=> v² - u² = 2as

Step-by-step calculations:

• Adding values from before calculations.

=> 0² - 25² = 2 × (-2.5) × s

=> 0² - 625 = -5s

=> 125 m

Therefore, 125 m is the distance travelled by the bus.