Momentum - Impuls
The momentum of an object depends on its mass and its velocity.
The momentum is directly proportional to its mass and directly proportional to its velocity. So,
$$\text{momentum} = \text{mass} \cdot \text{velocity}$$
In symbols,
$$p = m \cdot v$$
or
$$p = m v$$
Newton’s Second Law
Remember $$F = ma$$
and $$a = \frac{v-u}{t}$$
Combining the two formulae …
$${\begin{align} F & = ma \newline & = \frac{m(v-u)}{t} \newline & = \frac{mv-mu}{t} \end{align}}$$
Multiplying both sides by time t, we get:
$$\text{Force} \cdot \text{time} = \text{change in momentum}$$ or
$$Ft = {mv-mu}$$
Symbols and Units
- momentum p in
$kg \cdot ms^{-1}$ - mass m in kg
- velocities
$v, u$or$v_0, v_1$in$\frac{m}{s}$or$ms^{-1}$ - force F in N (which is equivalent to
$kg\cdot ms^{-2}$)