contestada

Kevin has a mass of 87 kg and is skating with in-line skates. He sees his 22-kg younger brother up ahead standing on the sidewalk, with his back turned. Coming up from behind, he grabs his brother and rolls off at a speed of 2.4 m/s. Ignoring friction, find Kevin’s speed just before he grabbed his brother.

Respuesta :

Answer:

[tex]V_ k = 3 m/s [/tex]  

Explanation:

Using the conservation of the linear momentum P:

[tex]P_i = P_f[/tex]

so:

[tex]M_kV_k = M_sV_s[/tex]

where [tex]M_k[/tex] is the mass of kevin, [tex]V_k[/tex] is the velocity of kevin before he grabs her brother, [tex]M_s[/tex] is the velocity of her brother and him after grabs her brother and [tex]V_s[/tex] is the velocity of both after the collition.

So, replacing the values and solving for Vk, we get:

[tex](87 kg)V_k = (87 kg+22 kg)(2.4m/s)[/tex]

[tex]V_ k = 3 m/s [/tex]

Otras preguntas