Question

The resistance r to the motion of a car is the square of the speed u . when the speed is 30km/h, the resistance is 190 newton's and when the speed is 50km/h, the resistance is 350 newtons.find for what speed the resistance is 302.5 Newton

Answer 1

R = k v^2
190 = k * 900 so k = 0.211
350 = k * 2500 so k = 0.14
baloney
perhaps they mean
R = a + k v^2
190 = a + 900 k
350 = a + 2500 k
---------------------
- 160 = 0 - 1600 k
k = 0.10
190 = a + 90
a = 100
so
R = 100 + 0.10 v^2
302.5 = 100 + 0.10 v^2
.1 v^2 = 202.5
v = 45 km/hr