Calculate k-Value for Car Drag Equation with Given Data

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AI Thread Summary
To calculate the k-value in the drag equation Fdrag = k*v^2 for a car with a maximum power of 60W at speeds of 120 km/h or above, the user has determined that the power is 57W between 30 km/h and 120 km/h. The car's mass is 1430 kg, and a table of time and velocity data is provided, although its relevance is uncertain. The user attempts to derive k by equating the power difference but finds the result unsatisfactory. Clarification on the correct approach to incorporate both power values and velocity is needed to accurately calculate k. Understanding the relationship between power, drag force, and velocity is crucial for solving the problem.
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Homework Statement


You have to find the value of k in the drag equation; Fdrag = k*v^2

It is for a car driving. The motors maximal effect is P = 60W, and it uses this, when the car drives 120 km/h or above.

Previously, I have calculated that between 30 km/h and 120 km/h, the resulting effect is P = 57W. How to calculate the k-value with these two values?
The mass of the car is 1430 kg.

If it helps, there is also given a tabel of the time and velocity:
t: 0 2,2 3,1 5,5 8,9 13,3 18,9 (s)
v: 0 30 40 60 80 100 120 (km/h)

However, this was for one of the previous questions, not sure if it ought to be used.


Homework Equations


Maybe F*v = P ?


The Attempt at a Solution


I think I have to focuse on the time, where v = 120km/t. Here I know v and I know the two P's.
So I though of an equation like this:

60W - k*v^2*v = 57 W

However, this gives a very strange k, so I think I am wrong. :(
 
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