m = mass of the airplane = 7 kg
r = radius of circle being traced by airplane = 5.6 meter
F = centripetal force acting on the airplane = 20 N
v = tangential velocity of the airplane
centripetal force acting on the airplane is given as
F = m v²/r
20 = 7 v²/5.6
20 x 5.6 = 7 v²
7 v² = 112
v² = 112/7
v² = 16
v = sqrt(16)
v = 4 m/s
hence the tangential velocity of the plane comes out to be 4 m/s
