Question

A car of mass thousand KG and a bus of mass 8000 KG are moving with the same velocity of 36 km/h find the forces to stop both the car in the bus in five seconds

Answer 1

$\checkmark$ Given:

A car of mass thousand KG and a bus of mass 8000 KG are moving with the same velocity of 36 km/h

$\checkmark$ To Find:

The forces to stop both the car in the bus in five seconds

$\checkmark$ Solution:

We know that,

$\red{\bigstar \ \boxed{\sf v=u+at}}$

Here,

• u = initial velocity
• v = final velocity
• a = acceleration
• t = time

Given that,

A car of mass thousand KG and a bus of mass 8000 KG are moving with the same velocity of 36 km/h

Hence,

• v = 0 m/s
• u = 36 km/h = 10 m/s
• t = 5 s

Substituting the values,

We get,

$\blue{\sf \implies 0=10+(a \times 5)}$

$\green{\sf \implies -10=5a}$

$\orange{\sf \implies a=\dfrac{-10}{5} \ m/s^{2}}$

$\sf \implies a=-2 \ m/s^{2}$

We know that,

$\pink{\bigstar \ \boxed{\sf F=ma}}$

Here,

• F = force
• m = mass
• a = acceleration

According to the question,

We are asked to find the forces to stop both the car in the bus in five seconds

Given that,

A car of mass thousand KG and a bus of mass 8000 KG are moving with the same velocity of 36 km/h

Hence,

• Mass of car = 1000 kg
• Mass of bus = 8000 kg

We found out that,

• a = -2 m/s²

$\star$ Force on car

$\blue{\sf \implies F=(1000 \times -2) \ N}$

$\green{\sf \implies F=-2000 \ N}$

$\star$ Force on bus

$\blue{\sf \implies F=(8000 \times -2) \ N}$

$\green{\sf \implies F=-16000 \ N}$

Answer 2

Answer:

Explanation:

Solution,

Here, we have

Mass of car = 1000 kg

Mass of bus = 8000 kg

Initial velocity of both = 36 km/h = 36 × 5/18 = 10 m/s

Final velocity of both = 0 m/s (As stoped)

Time taken by both = 5 seconds.

To Find,

Forces to stop the car and bus separately.

Formula to be used,

1st equation of motion, i.e

v = u + at

Newton's 2nd law, i.e

F = ma

At 1st we will find out acceleration,

v = u + at

⇒ 0 = 10 + a × 5

⇒ - 10 = 5a

⇒ - 10/5 = a

⇒ a = - 2 m/s².

Here, the acceleration is - 2 m/s.

Now, the forces,

Force on car,

F = ma

⇒ F = 1000 × (- 2)

⇒ F = - 2000 N

Force on bus,

F = ma

⇒ F = 8000 × (- 2)

⇒ F = - 16000 N.

Hence, the forces to stop car and bus are - 1000 N and - 16000 N.