A 2-kg bowling ball is accidentally dropped from a window and strikes the sidewalk at a speed of 30 m/s. It bounces back up with an initial speed of 20 m/s from the sidewalk. What is the magnitude of the impulse the sidewalk imparts to the bowling ball

Respuesta :

Answer:

[tex]I=20\ kg.m.s^{-1}[/tex]

Explanation:

Given:

mass of the ball, [tex]m=2\ kg[/tex]

initial speed of the ball before collision, [tex]u=30\ m.s^{-1}[/tex]

final speed of hte ball after collision, [tex]u=20\ m.s^{-1}[/tex]

We have mathematical relation for  impulse as:

[tex]I=F.dt[/tex] ......................(1)

From the Newton's second law of motion:

[tex]F=\frac{d}{dt} (p)[/tex]

[tex]F=m.\frac{dv}{dt}[/tex] ................................(2)

where:

[tex]dt=[/tex] time duration

[tex]dv=[/tex] change in velocity

[tex]dp=[/tex] change in momentum

Now from (1) & (2)

[tex]I=m.\frac{dv}{dt} .dt[/tex] (since this impulse is due to the impact force of the ball falling on the ground)

[tex]I=m.dv[/tex]

putting the values

[tex]I=2\times (30-20)[/tex]

[tex]I=20\ kg.m.s^{-1}[/tex] is the impulse transfer to the bowling by the sidewalk.