Oblique impact between a sphere and wall

Section 1: Understanding Oblique Impact

Comprehend that oblique impact refers to the collision where the direction of motion of an object is not along the line of impact.
Realise that in an oblique impact between a sphere and a wall, the sphere approaches the wall at an angle rather than straight on.
Understand that when collision occurs, the angle at which the sphere bounces off depends upon the angle of incidence, or the angle at which the sphere initially struck the wall.

Section 2: Principles of Oblique Impact

Grasp the key principle that the component of velocity perpendicular to the wall is reversed after the impact while the component of velocity parallel to the wall remains unchanged.
This is derived from the law of reflection, which states that the angle of incidence equals the angle of reflection.
Remember that these principles are applicable only in a perfectly elastic collision, where there is no loss of kinetic energy.

Section 3: Calculations and Formulae in Oblique Impact

Become familiar with the important formulae involved in oblique impact calculations. If the initial velocity is U at an angle θ to the normal, the components of velocity are: U cos θ (normal to the wall) and U sin θ (along the wall).
After the impact, the components become -U cos θ (reversed direction normal to the wall) and U sin θ (unchanged direction along the wall).
Learn to calculate the speed and direction after impact using these components.

Section 4: Problem-Solving in Oblique Impact

Apply the principles and formulae of oblique impacts to real-world problems. These may involve calculating the angle of incidence, speed before or after impact or the sphere’s direction.
Note that vector diagrams can be particularly useful in understanding and visualising these problems, as they allow you to see the components of the sphere’s movement.
Practice solving a wide variety of oblique impact problems to gain confidence. This problem-solving practice will deepen your understanding of how the principles of oblique impacts can be applied.