Because 2 ? rad = 1 rev, the angular displacement in part (b) corresponds to 2.2
ID: 2278262 • Letter: B
Question
Because 2? rad = 1 rev, the angular displacement in part (b) corresponds to 2.23 rev. In general, dividing the number of radians by 6 gives a good approximation to the number of revolutions, because 2? ~ 6. Question: If the angular acceleration were doubled for the same duration, by what factor would the angular displacement change?
Question: At what maximum speed can a car negotiate a turn on a wet road with coefficient of static friction 0.225 without sliding out of control? The radius of the turn is 27.0 m. (answer in m/s)
Explanation / Answer
a)
If the initial angular velocity was 0, then the angular displacement would double.
If the initial angular velocity was not 0, then we don't have enough data; but it would less-than-double.
b)
Friction force holds the car on the way while rotating.
Fnet = ma the only force pulling the car towards center is Ffriction so
above equation becomes
Ffriction= mv^2/r and by the formula Ffriction=kN=kmg
kmg=mv^2/r m cancels
v^2=kgr
applying the given;
v^2=0.225*9.8*27
v^= 59.535
v=7.715 m/s
take care