Abridge is made with segments of concrete 50 m long. if the linear expansion coefficient is 12  10–6 (°c)–1 , how much spacing (in cm) is needed to allow for expansion during an extreme temperature change of 150°f?

Amachinist turns the power on to a grinding wheel, at rest, at time t = 0 s. the wheel accelerates uniformly for 10 s and reaches the operating angular velocity of 96 rad/s. the wheel is run at that angular velocity for 40 s and then power is shut off. the wheel slows down uniformly at 1.5 rad/s2 until the wheel stops. in this situation, the time interval of deceleration is closest to: