Key idea
Momentum
p = mv · impulsion J = Δp = ∫Fdt
Linear momentum is the vector quantity p = mv. For an isolated system, total momentum remains constant.
Momentum
The key idea
Linear momentum is the vector quantity p = mv. For an isolated system, total momentum remains constant.
Why it matters
Momentum conservation is especially powerful for collisions and short interactions where internal forces may be large but cancel in the system total.
A picture to remember
Key idea
Momentum
Guided example
Momentum
Linear momentum is the vector quantity p = mv. For an isolated system, total momentum remains constant.
Put it into practice
Momentum
Choose a concrete case linked to Momentum. Write down the known information, what you are trying to find, and the units. Then state the rule, model or trend you will use. If a calculation is involved, keep the units visible at every line; if it is conceptual, state what changes and what remains fixed.
Check your answer
A strong answer contains four things: the starting situation, the variable that changes, the direction or numerical result, and one check. The check can be a unit, an order of magnitude, a limiting case or a comparison with a familiar example.