A 930 kg sports car collides into the rear end of a 2500 kg SUV stopped at a red light. The bumpers lock, the brakes are locked, and the two cars skid forward 2.6 m/s before stopping. The police officer, knowing that the coefficient of kinetic friction between tires and road is 0.80, calculates the speed of the sports car at impact.
what was the speed?
consider momentum change
momentum before= impulse to stop.
930*v=force*time= force*distance/avgvelocity
930V= mu*totalmass*g*distance*2/V
V=sqrt (2*mu*totalmass*g*distance/930)
I cant see anything wrong with this analysis.
I'm not sure why I keep getting the wrong answer, but I do.
Thanks for the help anyway :D
type the following into g00gl and the first result which will yah00answers will help you:The police officer, knowing that the coefficient of kinetic friction between tires and road is 0.80, calculates the speed of the sports car at impact.
blah blah blah
To calculate the speed of the sports car at impact, we can use the principle of conservation of momentum. According to this principle, the total momentum before the collision is equal to the total momentum after the collision.
First, let's calculate the initial momentum of the sports car and the SUV. The momentum (p) of an object is given by the product of its mass (m) and velocity (v): p = m * v.
The mass of the sports car is 930 kg, and its initial velocity is what we need to find. Let's call it v1.
The mass of the SUV is 2500 kg, and its initial velocity is 0 m/s since it is stopped at a red light.
Therefore, the initial momentum of the sports car is given by: p1 = m1 * v1 = 930 kg * v1.
After the collision, both vehicles come to a stop, so their final velocities are zero. The final momentum is then equal to zero.
The total initial momentum of both vehicles is equal to the total final momentum:
p1 + p2 = 0
Substituting the values:
930 kg * v1 + 2500 kg * 0 = 0
Simplifying the equation:
930 kg * v1 = 0
Dividing both sides of the equation by 930 kg:
v1 = 0
Therefore, the calculated speed of the sports car at impact is 0 m/s. The sports car was motionless at the moment of impact.