A 2kg bob is suspended by a 1m long string from the ceiling of a bus that accelerates horizontally at 2ms−2. When the bob is in equilibrium relative to the bus, what angle θ does the string make with the vertical?
a) θ≈21∘
b) θ≈78.5∘
c) θ≈11.5∘
d) θ≈14.4∘