In an American football game, a 90.6 kg fullback running east with a speed of 5.

Question

In an American football game, a 90.6 kg fullback running east with a speed of 5.00 m/s is tackled by a 94.3 kg opponent running north with a speed of 3.03 m/s.

(a) If the collision is perfectly inelastic, calculate the speed and direction of the players just after the tackle.

° (north of east)

(b) Determine the mechanical energy lost as a result of the collision.

Account for the missing energy.

Explanation / Answer

a). applying conservation of momentum in horizontal direction; 90.6*5 =(94.3+90.6) *Vx => Vx = 2.45 m/s applying conservation of momentum in vertical direction; 94.3*3.03 =(94.3 +90.6)*Vy => Vy = 1.545 m/s resulatnt velocity = sqrt(1.545^2 +2.45^2) = 2.896 m/s angle made with north = tan^-1(1.545/2.45) = 32.5 north of east b). loss of energy = 0.5*94.3*3.03^2 +0.5*90.6*5^2 - 0.5*(90.6+94.3)*2.896^2 = 790 J

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