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butz3
Oct17-04, 02:26 PM
i know that the formula for impulse is f(delta)t. my question ask " a truck with a mass of 1.20 x 10^3 kg has its brakes applied for 5.50s as it slows down from 24.0m/s, west to 10.4m/s west. determine the magnitude and direction of the impulse provided by the brakes." i know you need to use the formula
f(delta)t = m(delta)(vf-vi). but since i want the impulse do i just fill in the right side of the formula and git impulse or do i use the time also. thanks.

Fookie
Oct17-04, 02:38 PM
u can safely ignore "time=5.50s" as impulse is independant of time.


just impulse= (1.20 x 10^3)(24.0-10.4)

robphy
Oct17-04, 03:35 PM
The impulse is the left-hand-side: (Favg)(Delta t).
By the impulse-momentum theorem, it then follows that it is equal to the change-in-momentum.