On a very muddy football field, a 120 kg linebacker tackles an 85 kg halfback. Immediately before the collision, the linebacker is slipping with a velocity of 8.6 m/s north and the halfback is sliding with a velocity of 7.2 m/s east.a) What is the magnitude of the velocity at which the two players move together immediately after the collision?
b) What is the direction of this velocity ?

Respuesta :

Answer:

(a) 5.85 m/s

(b) 59.33 degrees North East

Explanation:

From the law of conservation of linear momentum, the sum of initial momentum equals the sum of final momentum.

East Momentum

[tex]mv = (M +m)v_e[/tex] where v and m represent velocity and mass, [tex]v_e[/tex] is common velocity, M is mass of linebacker while m is mass of halfback

[tex](85)(7.2) = (85 + 120)(v_e)\\v_e=2.985365854 m/s\\v_e\approx 2.99 m/s[/tex]

North Momentum

[tex]Mv = (m +M)v_n[/tex] where v and m represent velocity and mass, [tex]v_n[/tex] is common velocity, M is mass of linebacker while m is mass of halfback

[tex](120)(8.6) = (85 + 120)(v_n)\\v_n=5.034146341m/s \\v_n\approx 5.03 m/s[/tex]

Resultant velocity, [tex]v_r=\sqrt {v_e^{2}+v_n^{2}}[/tex]

Resultant velocity=[tex]\sqrt {2.99^{2}+5.03^{2}}=5.852780422 m/s\approx 5.85 m/s[/tex]

Direction=[tex]\tan^{-1}(\frac {v_n}{v_e})=\tan^{-1}(\frac {5.03}{2.99})=59.33107335\approx 59.33^{\circ}[/tex] North of East