Physics question, fairly simple for smarties out there :P

[fizix08]

Using the largest value of μ to solve the following problem. A 750kg car travels with an initial velocity of 25.0m/s on a surface with a coefficient of friction of ___. After a certain distance you come to rest.

a. You come to rest, what was the stopping force?
b. How long were you traveling before you came to rest?
c. What distance did you travel before you stopped?

Arghgh. I know this is a simple problem but I feel like I don't have enough information to solve, and I'm not sure what the problem means by the "largest value of μ". Thanks for any help.


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[jbsteele]

a] The stopping force can be calculated using the formula F = μmg, where μ is the coefficient of friction, m is the mass of the car (750kg), and g is the acceleration due to gravity (9.8 m/s2). Using the largest value of μ, the stopping force is 18,450N. To calculate the time it took for the car to come to rest, we need to use the equation t = v/a, where v is the initial velocity (25 m/s), and a is the acceleration. Since the car is decelerating, the acceleration is equal to the stopping force divided by the mass of the car (18,450N/750kg = 24.6 m/s2). Plugging in these values gives us a time of 1.02 seconds.[c] The distance traveled while the car was slowing down can be calculated using the equation d = vt, where v is the initial velocity (25 m/s) and t is the time calculated in (1.02 seconds). This gives us a distance of 25.5 meters.

 

[tomcue]

Response]:

Hello! It seems like you are trying to solve a kinematics problem using the coefficient of friction (μ) to determine the stopping force, time, and distance traveled. To answer your question, the largest value of μ refers to the maximum value of the coefficient of friction that can be applied in this problem.

To solve this problem, we can use the equation F = μmg, where F is the frictional force, μ is the coefficient of friction, m is the mass of the car, and g is the acceleration due to gravity (9.8 m/s²). Since we are looking for the stopping force, we can rearrange the equation to F = ma, where a is the acceleration of the car.

a. To find the stopping force, we need to first calculate the acceleration of the car. Using the kinematic equation v² = u² + 2as, where v is the final velocity (0 m/s), u is the initial velocity (25.0 m/s), and s is the distance traveled, we can solve for the acceleration. Plugging in the values, we get a = -25.0² / 2s. Now, we can use this value for acceleration in the equation F = ma to calculate the stopping force.

b. To find the time it takes for the car to come to a stop, we can use the kinematic equation v = u + at, where t is the time. Since we know the final velocity (0 m/s) and the initial velocity (25.0 m/s), we can solve for t. Plugging in the values, we get t = -25.0 / a.

c. To find the distance traveled before stopping, we can use the kinematic equation s = ut + 1/2at². Plugging in the values for u, t, and a, we get s = 25.0t + 1/2(-25.0² / 2s)t². We can solve for s by rearranging the equation to get a quadratic equation. Once we solve for the value of s, we will have the distance traveled before stopping.

I hope this helps! Remember, when solving physics problems, it's important to make sure all units are consistent and to use the appropriate equations for the given scenario. Keep practicing and you'll become a pro at solving these types of problems in no time!