Problem 5.25 A car at the Indianapolis 500 accelerates uniformly from the pit ar
ID: 1532629 • Letter: P
Question
Problem 5.25 A car at the Indianapolis 500 accelerates uniformly from the pit area, going from rest to 260 km/h in a semicircular arc with a radius of 220 m Part A Determine the tangential and radial acceleration of the car when it is halfway through the arc, assuming constant tangential acceleration. Express your answers using three significant figures separated by a comma AE Quan, R 3.77, 13.8 m /S Submit My Answers Give Up Incorrect; Try Again; 2 attempts remaining Part B If the curve were flat, what would the coefficient of static friction would be necessary between the es and the road to provide this acceleration with no slipping or skidding? Express your answer using three significant figures AE H5Explanation / Answer
The distance around the arc = (pi)220 = 691.15 m
260 km/h = 72.22 m/s
so, 72.22^2 = 2a(691.15)
or, a = 3.773 m/s^2
This is the tangential acceleration throughout the entire curve
The radial acceleration is v^2/r
Halfway around the arc is 345.575 m
v^2 = 2(3.773)(345.575)
v = 51.065 m/s
radial acceleration = 51.065^2/220 = 11.85 m/s^2
Total acceleration = sqroot(11.85^2 + 3.773^2)
= 12.436 m/s^2
The force of friction has to equal the force of car
m(12.436) = um(9.81)
m's cancel
u = 1.267