Impulse and Momentum – Real Life Examples

In our everyday lives, we encounter many situations where we experience a change in momentum. Whether it is a car stopping, a ball being thrown, or a person jumping, all these scenarios involve the concepts of impulse and momentum. These physical quantities are fundamental in understanding how objects move and interact with each other. Let’s take a deeper look at these concepts and see how they apply to real-life situations.

Motion

Momentum is a measure of the amount of motion of an object. It is the product of an object's mass and its velocity. The heavier and faster an object moves, the greater its momentum. Mathematically, momentum (p) is expressed as:

p = m * v

Where:

• p is the speed
• m is the mass of the object
• v is the velocity of the object

Imagine you have two objects: a bowling ball and a basketball. You spin both at the same speed. Even though their velocities are equal, the bowling ball has more speed because it has more mass. This explains why a bowling ball is more difficult to stop once it starts rolling than a basketball.

Imagination of motion

Consider the following example:

|--------| |===> velocity |Ball 1 | --> |Ball 2 | (after collision) |--------| |========| mass = 5kg mass = 10kg

Ball 1 of mass 5 kg collides with ball 2. After the collision, ball 1 transfers some of its momentum to ball 2.

Impulse

Impulse is the change in the momentum of an object. It occurs when a force is applied to an object over a period of time. The concept of impulse states that even a small force can have a huge effect if applied over a long period of time. The impulse experienced by an object is equal to the change in its momentum.

Impulse (J) is given by the formula:

J = F * Δt

Where:

• J is the impulse
• F is the applied force
• Δt is the time period for which the force is applied

Real life example of impulse

Consider a soccer player kicking a ball. The player's foot is in contact with the ball for only a fraction of a second. However, during this short contact time, a large force is applied to the ball, causing a significant change in its momentum. This sudden change is a demonstration of impulse.

Relation between impulse and momentum

The impulse-momentum theorem states that the impulse on an object is equal to the change in its momentum. In formula form, this is expressed as:

J = Δp

This means:

F * Δt = m * Δv

Where Δp is the change in momentum and Δv is the change in velocity.

Application of impulse and momentum in sports

Sports provide many examples of impulse and momentum. Let's look at a few:

Soccer

In football, players are often tackled, which involves changing their momentum. The impulse imparted during a tackle depends on how quickly and with what force the other player tackles.

Baseball

When a baseball bat hits a ball, the force applied by the bat for a limited time causes a change in momentum due to the contact with the ball, causing the ball to move forward. A fast pitch changes direction quickly due to the impulse given by the bat.

Basketball

Basketball players use their hands to change the ball's motion. For example, when dribbling, a player applies a brief moment of force to change the ball's speed and direction while maintaining control of the ball.

Safety applications: car accidents

The principles of impulse and momentum are used heavily in designing safety features in cars, such as airbags and seatbelts. During a collision, the change in momentum is important.

Seatbelts increase the duration of a crash. By stretching a little, the force on the passenger is spread out over a longer period of time, reducing the force of impact.

Visualizing a car accident

|==== Car hits ===| | Wall | ----> | Stop

Without safety features, the impulse is delivered in too short a time, resulting in high forces, which can cause injury.

Elastic and inelastic collision

Based on the conservation of kinetic energy, collisions can be divided into two categories: elastic and inelastic.

Elastic collision

In an elastic collision both momentum and kinetic energy are conserved. A great example of this is two billiard balls hitting each other on a pool table.

|Ball A | ---> |===| collision -----> |Ball B |

Both momentum and kinetic energy remain the same before and after the collision.

Inelastic collision

In an inelastic collision, momentum is conserved, but kinetic energy is not. An example of this is a car crash, where much of the kinetic energy is converted to other forms of energy, such as sound and heat, and is thus not conserved.

|Car A | ---> |====| collision -----> |Car A&B|

The momentum remains constant before and after the collision, but the energy is dissipated to the surroundings.

Impulse control in daily tasks

We can see our control over impulse in many daily activities. For example, when catching a ball, we naturally bring our hands back when they come in contact with the ball. This increases the time for the impulse to act, which reduces the force effect and allows a more controlled grip.

Similarly, in sports such as golf or tennis, players learn to move forward with their swing. This action helps to increase the time the force is applied to the ball, maximizing the change in momentum and thus increasing the speed of the ball.

Newton's laws of motion and their relation to impulse and momentum

The concepts of impulse and momentum are deeply rooted in Newton's laws of motion. For example, Newton's second law can be expressed in terms of momentum as follows:

F = Δp / Δt

Here, the force is directly related to the change in momentum with respect to time. This shows that for a constant mass, the change in velocity (or acceleration) is directly proportional to the applied force.

Newton's third law comes into effect

Newton's third law, which states that for every action there is an equal and opposite reaction, can also be seen in impulse scenarios. When a swimmer pushes against the pool wall, the impulse of the force applied by the swimmer results in an equal and opposite impulse applied by the wall, which pushes the swimmer forward.

Conclusion

Impulse and momentum are integral aspects of motion and are evident in many aspects of daily life and complex engineering systems alike. Understanding these concepts helps us understand how forces interact over time and how motion is affected by various influences. From the dynamics of sports to safety features in vehicles, impulse and momentum play a vital role in describing how objects move and interact.

Comments