Question

A ball of mass 0.1kg is thrown against a wall.It Strikes the wall normally with a velocity of 30 m/s and it rebonds with a velocity of 20m/s. Calculate the impulse of the force entered by the wall on the ball?​

Answer 1

Given :

• Mass of the ball = 0.1 kg.

• Initial velocity = 30 m/s.

• Final Velocity = 20 m/s.

To find :

Impulse imparted on the ball.

Solution :

We know the formula for impulse i.e,

$\boxed{\bf{I = m(v - u)}}$

Where :-

• I = Impulse
• m = Mass of the body.
• v = Final Velocity
• u = Initial Velocity.

Now using the above equation and substituting the values in it, we get :

$:\implies \bf{I = m(v - u)}$

$:\implies \bf{I = 0.1 \times (20 - 30)}$

$:\implies \bf{I = 0.1 \times -10}$

$:\implies \bf{I = -1}$

$\boxed{\therefore \bf{Impulse = -1\:kg\:ms^{-1}}}$

Hence the Impulse imparted by the ball is -1 kg m/s.

Additional Information :-

Definition of Impulse :

Impulsive force or impulse is a application of a large amount of force , acting on a body for a short time interval.

Impulse = Force × Time

We know that Force is the Product of Mass and Acceleration , so by substituting it in the equation , we get :

==> Impulse = m a t

We also know that Acceleration is the Rate of change in velocity.

By substituting it in the equation , we get :

==> Impulse = m × (v - u)/t × t

==> Impulse = m(v - u).

∴ Impulse = m(v - u)

Hence Derived !!

Dimension Formula for Impulse :

Impulse = M¹L¹T-¹

Answer 2

We know the formula for impulse i.e,

Where :-

I = Impulse

m = Mass of the body.

v = Final Velocity

u = Initial Velocity.

Now using the above equation and substituting the values in it, we get :

Hence the Impulse imparted by the ball is -1 kg m/s.

Additional Information :-

Definition of Impulse :

Impulsive force or impulse is a application of a large amount of force , acting on a body for a short time interval.

Impulse = Force × Time

We know that Force is the Product of Mass and Acceleration , so by substituting it in the equation , we get :

==> Impulse = m a t

We also know that Acceleration is the Rate of change in velocity.

By substituting it in the equation , we get :

==> Impulse = m × (v - u)/t × t

==> Impulse = m(v - u).