May I please get help with those questions..i am so stuck... Thank you very much
ID: 1998724 • Letter: M
Question
May I please get help with those questions..i am so stuck... Thank you very much 7.4 The flywheel of a steam engine runs with a constant angular velocity of 150 When the steam is shut off, a constant frictional forces acting at the bearings stops the wheel in 2.20 hours. (a) What is the angular acceleration of the flywheel, in revs/min during the slowdown? (b) How many revolutions does the wheel make before stopping? (c) At the instant the flywheel is turning at 75 rpm, what is the tangential acceleration, in m/s2, of a point on the wheel that is 50 cm from the axis of rotation? (d) What is the magnitude of the net acceleration of the point in part (c) 7.5 The blades of a propeller are 80.0 cm long. At one point the propeller is spinning with an angular speed of 10.0 rad/s and the angular speed is increasing at 50.0 rad/s (a) Find the tangential and centripetal acceleration of the tip of a propeller blade (b) Find the magnitude of the net acceleration of the tip. Clearly the angular acceleration cannot remain at 50.0 rad/s2 indefinitely since there must be a limit to the speed the tip of the blades. What factors would determine this limit?Explanation / Answer
7.4 a) angular acceleration alpha = dw/dt
= (0-150)/(2.2*60)
= -1.136 rev/min^2
b) by third equation of rotation,
revolutions = w^2/2alpha
=150^2 /(2*1.13636)
= 9900 revolutions
c) at = [1.13636*2pi/(60*60)]*0.50 = 0.00099166 m/s^2
d) v = wr = 75*2pi/60*0.50
= 3.927 m/s
ar = 3.927^2/0.5 = 30.84 m/s^2
net acceleration = 30.84 m/s^2