A ceiling-fan blade of length 0.40m starts from rest and reaches an angular speed of 200rev⋅min−1 in 6.0s under constant angular acceleration. What is the magnitude of the tangential acceleration of the blade tip during this interval?
a) 8.4ms−2
b) 0.70ms−2
c) 1.4ms−2
d) 2.8ms−2