Question

(i)How much force is required to stop a body whose mass is100kg and moves initially
with a velocity of 50m/s. The displacement made by it is 5m.​

Answer 1

Answer:

• Force required to stop the body = 25000 N

      (In the direction opposite to motion of body)

Explanation:

Given:

• Mass of body, m = 100 kg
• Initial velocity of body, u = 50 m/s
• Final velocity of body, v = 0  [ since, it is being brought to rest ]
• Displacement made by body, s = 5 m

To find:

• Force required to stop the body, F =?

Formulae required:

• Third equation of motion

       2 a s = v² - u²

• Newton's second law of motion

      F = m a

[ Where v is final velocity, u is initial velocity, a is acceleration, s is distance covered, F is force required and m is mass of body ]

Solution:

Let, acceleration of body be a then,

Using third equation of motion

→ 2 a s = v² - u²

→ 2 a ( 5 ) = ( 0 )² - ( 50 )²

→ 10 a = -2500

→ a = -250 m/s²

Now, Let the force required to stop the body be F then,

Using Newton's second law of motion

→ F = m a

→ F = ( 100 ) · ( -250 )

→ F = -25000 N

Therefore,

• Force required on the body to stop it is 25000 Newton in the direction opposite to the motion of body.