Question

a gas powered model airplane has a mass of 2.50 kilograms. A student exerts a force on a cord to keep the airplane flying around her at a constant speed of 18.0 meters per seond in a horizontal, circular path with a radius of 25.0 meters. what is the magnitude of the centripetal force exerted on the air plane to keep it moving in this circular path

Answer 1

The first thing to do in this case is a free-body diagram in the radial direction.From the free body diagram you get that
Fc = m * ar
where
Fc: Centripetal force
m: mass
ar: radial acceleration
By definition
ar: v ^ 2 / r
where
v: speed
r: radio
Substituting the values
Fc = m * (v ^ 2 / r)
Fc = (2.50 * ((18 ^ 2 / (25)) = 32.4N
answer
the magnitude of the centripetal force exerted on the air plane to keep it moving in this circular path is 32.4N