Exam Questions - Momentum and impulse
Exam Questions - Momentum and impulse
Section 1: Identifying Momentum and Impulse Questions
- Spot that a momentum and impulse question typically involves a collision or a sudden change in movement.
- Look for language indicating an object changing speed or direction, such as “impact”, “collision”, “braking”, “bouncing”, “turning sharply”, or “starts to move”.
- Be aware that both single-body and multiple-body scenarios can be presented in these types of questions.
Section 2: Key Concepts and Formulas
- Recall that momentum is the product of an object’s mass and its velocity.
- Remember that impulse is change in momentum, or the product of force and time.
- Understand that Newton’s Second Law, force equals rate of change in momentum, is crucial in these questions.
- Recall the formula for impulse: Impulse = change in momentum = Force x time
Section 3: Applying Conservation of Momentum
- Understand that total momentum before an event (collision, impact, etc.) is equal to total momentum after an event.
- Apply this understanding to solve problems in a straight line or in two dimensions, using vector components if necessary.
- As momentum is vectorial in nature, remember to take into account the direction of motion.
Section 4: Problem-Solving Approach
- Use accurate diagrams to represent the problem, showing initial and final states especially when dealing with vectors.
- Use the principle of Conservation of Momentum to form one equation.
- Apply Newton’s Second Law, force equals rate of change in momentum, to form another equation whenever a force is exerted for a definite period of time.
- Be ready to use simultaneous equations to resolve problems that provide insufficient information for a direct solution.
Section 5: Dealing with Coefficient of Restitution
- Be ready for questions involving the Coefficient of Restitution (e-value), representing the relative speeds before and after a collision.
- Be aware that this often involves a combination of momentum, impulse, and kinetic energy principles.
- Recall that Conservation of Momentum applies even when collisions are not perfectly elastic.
Section 6: Practice Makes Perfect
- Persist with past paper questions to gain experience with the various scenarios that can be presented.
- Master the art of quickly identifying the key details and deciding the most effective problem-solving approach.
- Regularly reviewing solutions and understanding mistakes will build confidence and mastery over time.