A 920 kg sports car collides into the rear end of a 2300 kg SUV stopped at a red light. The bumpers lock, the brakes are locked, and the two cars skid forward 2.5 m before stopping. The police officer, knowing that the coefficient of kinetic friction between tires and road is 0.42, calculates the speed of the sports car at impact. What was that speed? I still help that wasn't the right answer what did I do wrong?
NVM I got it!!
To calculate the speed of the sports car at impact, you can use the principle of conservation of momentum. The equation for conservation of momentum is:
m1v1 + m2v2 = m1v1' + m2v2'
Where:
m1 = mass of the sports car (920 kg)
m2 = mass of the SUV (2300 kg)
v1 = initial velocity of the sports car (unknown)
v2 = initial velocity of the SUV (0 m/s as it is stopped)
v1' = final velocity of the sports car (0 m/s as it comes to a stop)
v2' = final velocity of the SUV (also 0 m/s as it comes to a stop)
We can simplify the equation because the final velocities of both cars are 0:
m1v1 + m2v2 = 0
Since v2 is 0, we can further simplify the equation to:
m1v1 = 0
Now, we can solve for the initial velocity of the sports car (v1):
v1 = 0 / m1
v1 = 0 m/s
Therefore, the initial velocity (or speed) of the sports car at impact is 0 m/s.
If you obtained a different answer, it's possible that there was an error in the calculations or an incorrect assumption. Make sure to double-check the values used for mass and the data given in the problem statement.