Three impulse rows hold force fixed while contact time changes, making the accumulated momentum change visible.

Example

A fixed force delivers more impulse when contact lasts longer. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Hold force fixed and scan contact time

Impulse is force accumulated over contact time. The force arrow stays the same; the timer decides the momentum change.

J=FΔtJ = F\Delta t

Brief contact

A 4 N push for 1 s gives impulse 4 kg*m/s.

J=FΔt=4 N1 s=4 kgm/sJ = F\Delta t = 4\ \text{N}\,\cdot\,1\ \text{s} = 4\ \text{kg}\,\text{m}/\text{s}
Cart relation rowA cart on level ground carries only the arrows used by this row.F

Middle contact

The same push for 2 s gives impulse 8 kg*m/s.

J=FΔt=4 N2 s=8 kgm/sJ = F\Delta t = 4\ \text{N}\,\cdot\,2\ \text{s} = 8\ \text{kg}\,\text{m}/\text{s}
Cart relation rowA cart on level ground carries only the arrows used by this row.F

Long contact

The same push for 3 s gives impulse 12 kg*m/s.

J=FΔt=4 N3 s=12 kgm/sJ = F\Delta t = 4\ \text{N}\,\cdot\,3\ \text{s} = 12\ \text{kg}\,\text{m}/\text{s}
Cart relation rowA cart on level ground carries only the arrows used by this row.F

Longer contact accumulates more impulse

Each row uses the same force. Contact time is the only changing input, and the impulse grows row by row.

FΔtJ4 N1 s4 kgm/s4 N2 s8 kgm/s4 N3 s12 kgm/s\begin{array}{c|c|c}F & \Delta t & J \\ \hline 4\ \text{N} & 1\ \text{s} & 4\ \text{kg}\,\text{m}/\text{s} \\ 4\ \text{N} & 2\ \text{s} & 8\ \text{kg}\,\text{m}/\text{s} \\ 4\ \text{N} & 3\ \text{s} & 12\ \text{kg}\,\text{m}/\text{s}\end{array}
mechanics A 4 N push lasting 1 s, 2 s, and 3 s gives impulses 4 kg*m/s, 8 kg*m/s, and 12 kg*m/s.