Awheel on a watermill turns halfway every 4.0 s. what is the wheel's angular velocity? a. 0.39 rad/s b. 2.5 rad/s c. 3.1 rad/s d. 0.79 rad/s e. 13 rad/s

A revolution equals 2*pi radians.
 As the wheel rotates half every 4 seconds, then it means that it rotates half revolution.
 Thus, the angular velocity of the wheel is given by:
 w = (pi) / (4) = 0.79 rad / sec
 answer
 The wheel's angular velocity is 0.79 rad / sec

Initial velocity,  u = 4.9 m/sfinal velocity = v m/sinitial height,  h₁ =  245 m    final height, h₂ = 0a = -9.8  m/s²time taken = t secondss = ut + 0.5at²⇒  (h₂-h₁) = ut + 0.5at²⇒  0-245 = 4.9t + 0.5×(-9.8)×t²⇒ -245 = 4.9t - 4.9t²⇒ 4.9t² -4.9t -245 =0solving it, we get   t = 7.59sv  = u +  at = 4.9 -9.8×7.59 = 4.9 - 74.38 = -69.48 m/svelocity is  69.48 m/s downward

When seismic waves hit a fault, the waves are reflected off the fault. seismograph can detect these reflected seismic waves. geologists then use these data to map the fault's length and depth