- Linear momentum is defined as the product of mass and velocity - It is a measure of an object's resistance to stop. - The units are \( \mathrm{kgms}^{-1} \) \[ \text { momentum }=\text { mass } \times \text { velocity } \] - For example, that a body of mass 2 kg travelling \( 3 \mathrm{~ms}^{-1} \) has a momentum of \( 6 \mathrm{kgms}^{-1} \). A body of the same mass travelling at the same speed but in the opposite direction has a moment of \( 6 \mathrm{kgms}^{-1} \) Example 1 A trolley has a mass of 30 Kg . The trolley is moving at a constant (uniform) velocity of \( 2 \mathrm{~ms}^{-1} \) to the right. Calculate the momentum of the trolley. Example 2 calculate the momentum of a cruise tuner of mass 20000 tonne when travelling at \( 6.0 \mathrm{~ms}^{-1}(1 \) tonne \( =1000 \mathrm{~kg}) \)

Momentum has a fascinating history in physics! Originally, the concept was linked to Aristotle's ideas about motion, but it wasn't until Newton's laws of motion that momentum was rigorously defined. Newton introduced the derivative concepts of force and mass, laying the framework for understanding momentum as a quantity crucial to the laws of conservation—meaning in a closed system, momentum is conserved, just like a game of marbles where no marbles are allowed to leave the table! When applying linear momentum in the real world, think about traffic accidents or sports! For instance, when a car collides with another vehicle, momentum conservation dictates that the total momentum before and after the crash remains constant, allowing engineers and safety experts to design better safety features. In sports like soccer or basketball, understanding how players can alter their momentum during play can improve strategies for passing and shooting. Who knew physics could lead to better goals?