need help with physics 11 question?
Drag race tires on asphalt have a very high coefficient of friction. If a race car finishes a quarter-mile (402m) in 6.0s, what is the coefficient of static friction? (Assume the tires don't slide, the car accelerates uniformly, no air resistance).
- Andrew SmithLv 71 month ago
The coefficient of friction is the horizontal ( friction ) force / normal reaction. = ma / mg = a/g
the acceleration can be found from s= 1/2 a t^2 -> a = 2s/ (t^2)
-> coefficient = (2s/(t^2)) / g = 2*402/(6^2 * 9.8) = 2.28 +- 0.01
- billrussell42Lv 71 month ago
d = ½at²
a = 2d/t² = 804/36 = 22.3 m/s²
F = ma = 22.3m
w = mg = 9.8m
μ = force of friction/weight = 22.3/9.8 = 2.28