Homework Help: Physics

Posted by Shaila on Monday, October 4, 2010 at 8:41am.

A car with mass of 1875kg is traveling along a country road when the driver sees a deer dart out onto the road. The driver slams on the brakes manages to stop before hitting the deer. The driver of a second car with 2135kg is driving too close and does not see the deer. When the driver realizes that the car ahead is stopping, he hits the brakes but is unable to stop. The cars lock together and skid another 4.58m. All of the motion is along a straight line. If the coefficient of friction between the dry concrete and rubber tires is 0.750, what was the speed of the second car when it hit the stopped car?

Physics - drwls, Monday, October 4, 2010 at 12:40pm
First solve for the speed of the cars locked together, V', using the fact that the kinetic energy lost equals work done against friction during the skid.
(1/2)(M+m)V'^2 = (M+m)(Uk)*g*X
V'^2 = 2*0.750*9.8*4.58 = 63.3 m/s^2

Then apply conservation of momentum to determine the speed of the faster car that caused the collision, V.
M V = (M+m)*V'

Solve for V

Answer this Question

Related Questions

physics - A driver in a car traveling at a speed of 55.3 mi/h sees a deer 108 m ...
Physics - A driver in a car traveling at a speed of 56.0 mi/h sees a deer 116 m ...
Physics - A driver in a car traveling at a speed of 56.0 mi/h sees a deer 116 m ...
physics - A driver in a car traveling at a speed of 70 mi/h sees a deer 90 m ...
physics - A driver in a car traveling at a speed of 41.7 mi/h sees a deer 88 m ...
AP Physics - A driver in a car traveling at a speed of 62 mi/h sees a deer 112 ...
physics - A driver in a car traveling at a speed of 59 mi/h sees a deer 104 m ...
P - A driver in a car traveling at a speed of 56 mi/h sees a deer 91.2 m away on...
Physics - A car is being driven along a country road on a dark and rainy night ...
physics - A driver in a car traveling at a speed of 60 mi/h sees a deer 100 m ...

For Further Reading

First Name:
School Subject:
Answer: