Car crash stimulus calculations

[omgplshelpme]

there is a car crash where car A is resting at the traffic lights and car B is driving at 100km/hr and at 45m saw the car and stepped on the brakes.

the velocity of car B is 27.8m/s
the deceleration is -6.7 m s^-2
the thinking distance is 41.7m
weight of car B is 1385 kg
weight of car A is x

i have to calculate the momentum, force, coefficient force and velocity etc...

i really need help

ty

 

[tiny-tim]

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[omgplshelpme]

ok i have calculated the momentum of both cars and the momentum before the collision is greater then the momentum after the collision, have i done something wrong? momentum before is suppose to equal momentum after

ah I am so confused

 

[tiny-tim]

hi omgplshelpme!

show us your full calculations ​

 

[rwisz]

I can provide some guidance on how to approach these calculations. First, we need to define some variables and equations that will help us solve the problem. Let's start with the basic equation for momentum, which is mass times velocity (p = mv). In this case, car B has a mass of 1385 kg and a velocity of 27.8 m/s, so its momentum would be 38,473 kg*m/s.

Next, let's consider the forces at play in this car crash. The car B is decelerating, which means there is a force acting in the opposite direction of its motion. We can use Newton's second law, which states that force (F) equals mass (m) times acceleration (a) to calculate the force on car B. In this case, the deceleration is -6.7 m/s^2 and the mass is 1385 kg, so the force would be -9294.5 N. This negative value indicates that the force is acting in the opposite direction of the car's motion.

To calculate the coefficient of friction, we need to consider the normal force (N) and the force of friction (Ff). The normal force is equal to the weight of the car (mg), so for car B it would be (1385 kg)(9.8 m/s^2) = 13,573 N. The force of friction can be calculated using the equation Ff = μN, where μ is the coefficient of friction. Rearranging this equation, we get μ = Ff/N. Therefore, the coefficient of friction for car B would be -9294.5 N / 13,573 N = -0.684.

Finally, we can calculate the velocity of car A using the conservation of momentum principle, which states that the total momentum before and after a collision must be equal. Since car A is stationary, its initial momentum is zero. Therefore, the final momentum of the two cars must also be zero. We can set up an equation using the masses and velocities of the two cars to solve for the velocity of car A. This would be (1385 kg)(27.8 m/s) + (x kg)(0 m/s) = 0. Solving for x, we get x = -38,473 kg*m/s / 0 m/s = 0 kg. This means that car A has no mass, which is