impulse

noun

• 1a sudden strong and unreflective urge or desire to act:I had an almost irresistible impulse to giggle
• [mass noun] the tendency to act impulsively:he was a man of impulse, not premeditation

• 2something that causes something to happen or happen more quickly; an impetus:an added impulse to this process of renewal

• 3a pulse of electrical energy; a brief current:nerve impulses electrical impulses

• 4 Physics a force acting briefly on a body and producing a finite change of momentum: ability to communicate motion by impulse
• a change of momentum produced by an impulse, equivalent to the average value of the force multiplied by the time during which it acts.