1) Helicopter blades withstand tremendous stresses. In addition to supporting the weight of a helicopter, they are spun at rapid rates and experience large centripetal accelerations, especially at the tip. (For each answer, enter a number.)

(a)Calculate the magnitude (in m/s²) of the centripetal acceleration at the tip of a 3.30 m long helicopter blade that rotates at 345 rev/min. m/s²

(b) Compare the linear speed of the tip with the speed of sound (taken to be 340 m/s).

v_tip/v_sound =

2) (a) A 19.0 kg child is riding a playground merry-go-round that is rotating at 50.0 rev/min. What centripetal force (in N) must she exert to stay on if she is 1.50 m from its center? (Enter a number.) N

(b) What centripetal force (in N) does she need to stay on an amusement park merry-go-round that rotates at 3.00 rev/min if she is 7.00 m from its center? (Enter a number.) N

(c)

Compare each force with her weight. (For each answer, enter a number.)

(force from (a))/(weight) =

(force from (b))/(weight) =