Question

a car of mass 1000 kg is moving with a velocity 72 kg/hr the driver applies breaks and slows down the velocity to 36 kg/hr over a distance of 40 m. How much force was applied to slowdown the car ?​

Answer 1

Given :-

• Mass of the car is 1000 kg
• Initial velocity is 72 km/hr
• Final velocity is 36 km/hr
• Distance covered is 40 m

To calculate :-

• Force required?

EXPLANATION :-

Firstly let's convert the velocities of the body km/hr - m/s

Initial velocity => 72 km/hr

= 72 × 5/18 m/s

Initial velocity (u) = 20 m/s

Final velocity => 36 km/hr

= 36 × 5/18 m/s

= 10 m/s

Final velocity (v) = 10 m/s

Now,

By using 1st equations of motion.

v = u + at where,

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

Substituting the values,

10 = 20 + at

-10 = at

a = -10/t ------ eq-1

Now, by using third equation of motion

v² - u² = 2as where,

• v = final velocity
• u = initial velocity
• a = acceleration
• s = distance covered

Substituting the values,

(10)² - (20)² = 2 × -10/t × 40

100 - 400 = -800/t

-300 = -800/t

3 = 8/t

t = 8/3 s

So, time taken is 8/3 s

As we know that,

Acceleration is (a) = v-u/t

Substituting the values,

a =( 10-20) / 8/3

a = -10/8/3

a = -30/8

a = -15/4 m/s²

Now, force required is

As we know that Force is product of mass and acceleration.

F = m × a

F = 1000 × -15/4

F = 250 × -15

F = -3,750 N

So, force required for the body is -3750N

Answer 2

Answer:

Answer: The momentum will be 45000 m/s.

Explanation:

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