driving North through an intersection in a 55 mph speed zone, Police, who is dri

Question

driving North through an intersection in a 55 mph speed zone, Police, who is driving is new Cadillac and approaching the intersection from the West, hits you broadside. The two cars stick together and skid a distance 46.2 mwith locked wheels at an angle of 67.2° to the East of North. The mass of your car is 1516.0 kg while the Cadillac has a mass 2089.0 kg. The coefficent of sliding friction is 0.60. The Chief of Police is angry that you have damaged his new Cadillac and gives you a ticket for speeding. The local judge is going to believe his Chief of Police rather than some out-of-town student. You realize that the knowledge you learned in your physics course is your only hope for acquittal. Compute the speed of the Chief of Police immediately prior to the collision.

Explanation / Answer

Here ,

for the car ,

acceleration, a = -u * g

a = -0.60 * 9.8

a = -5.88 m/s^2

distance , d = 46.2 m

Now , initial velocity while skiding is v m/s

v = sqrt(2 *a * d)

v = sqrt(2 * 46.2 * 5.88)

v = 23.31 m/s

Now , for the conservation of momentum in north direction

23.31 * cos(67.2) * (1516 + 2089) = u * 2089

u = 15.6 m/s

speed of cadillac = 15.6 * 3600/1609

speed of cadillac = 34.9 mph

the speed of the Chief of Police immediately prior to the collision is 34.9 mph

Related Questions

Navigate

• Browse (All)
• Browse D
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.