a. Read thequestions below, and label the pictorial representation below withall

Question

a. Read thequestions below, and label the pictorial representation below withall appropriate quantities labeled distinctly.


b. Determine, ifpossible, the speeds of the sports car immediately before thecollision and immediately after the collision. Was the sports carspeeding before the collision? The speed limit is 55 mph (about 25m/s) on the the road where the accident took place. In a court hearing, you are called as an expertwitness. A police officer reconstructs an accident in the followingway: A sport car of mass m1 = 1000 kg collided with a parked pickuptruck of mass m2 = 1500 kg. From the skid marks, it is estimatedthat the speed of the pickup immediately after the collision was21.6 m/s, at an angle of 33.7 ° with the direction of theroad. The sports car left a mark at an angle of 60 ° withthe road.
a. Read thequestions below, and label the pictorial representation below withall appropriate quantities labeled distinctly.



b. Determine, ifpossible, the speeds of the sports car immediately before thecollision and immediately after the collision. Was the sports carspeeding before the collision? The speed limit is 55 mph (about 25m/s) on the the road where the accident took place.

Explanation / Answer

m v = m v2 cos 33.7 + M V cos 60   v = sports car & V = truck   (x-components ofmomentum)    (I) m v2 sin 33.7 = M V sin 60    y-component of momentum zero before and after collision (II) M V = m v2 (sin 33.7 / sin 60) = .641 mv2      (III) m v = m v2 (.831 + .320)   = 1.15m v2  equation(I)      (IV) M V = .641 * m v / 1.15     using (IV)& (III) v = (1.15 / .641) * (1500 / 1000) * 21.6 = 58.1m/s     the speed of the sports car before thecolllision The sports card was speeding From (III)   v2 = (M / m) * V / .641 =1.5 * 21.6 / .641 = 50.5 m / s   after thecollision m v = m v2 (.831 + .320)   = 1.15m v2  equation(I)      (IV) M V = .641 * m v / 1.15     using (IV)& (III) v = (1.15 / .641) * (1500 / 1000) * 21.6 = 58.1m/s     the speed of the sports car before thecolllision The sports card was speeding From (III)   v2 = (M / m) * V / .641 =1.5 * 21.6 / .641 = 50.5 m / s   after thecollision

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