A wheel spins in the counterclockwise direction.
(a) If its initial angular velocity was +7.13 rad/s and it rotated an angular displacement of +13.5 revolutions before coming to rest, what was its angular acceleration vector?
(b) How long did the wheel rotate?
Im confused on which equations to use to approach the problem, please help!
2007-11-07 14:24:55 · 2 answers · asked by =P 6 in Science & Mathematics ➔ Physics
a) -0.30 rad/s^2
b) t= 23.8 s
use the equation Wf^2=Wi^2+2ab
where a is angular acceleration and b is angular displacement. (don't know how to write alpha and theta).
2007-11-07 14:37:58 · answer #1 · answered by jenni m 2 · 1⤊ 0⤋
Do you remember s = v^2/(2a), and t = v/a from translation kinematics?
Here is the same idea in rotationese:
A. s = v^2/(2a); theta = omega^2/(2alpha); alpha = omega^2/(2theta) = -0.3 rad/s^2 (remember to express theta in rad.)
B. t = v/a; t = omega/alpha = 23.79 s
2007-11-07 14:38:40 · answer #2 · answered by kirchwey 7 · 1⤊ 0⤋