3.) A car with a mass of 2,000 kg travels at 20 m/s. Which one has the greatest impulse?A) The car slows to a stop in 10 s for a red light.B) The car slams on the brakes and comes to a stop in 4s to avoid running into the car in front of it.C) The car slams into a wall coming to a stop in 1.2 s.

3 A car with a mass of 2000 kg travels at 20 ms Which one has the greatest impulseA The car slows to a stop in 10 s for a red lightB The car slams on the brakes class=

Respuesta :

Given that the mass of the car is m = 2000 kg and initial speed u = 20 m/s.

Here, three values of time are given.

(a) t1 = 10 s

(b) t2 = 4 s

(c) t3 = 1.2 s

In all three cases, the final velocity vis zero.

Impulse = change in momentum

= mv-mu

[tex]\begin{gathered} \operatorname{Im}\text{pulse = 2000}\times0-2000\times20 \\ =-40000\text{ Kg m/s} \end{gathered}[/tex]

If the time duration is increased then force will be decreased as

[tex]\operatorname{Im}\text{pulse = force}\times time[/tex]

Force will be lowest for 10s and greatest for 1.2 s.

The impulse will be the same for all three cases as the change in momentum is the same.