Equal the tension of the line to the force needed to stop (deselerate) the mass from a speed of 9.2 ft/s to 0 in 4.4 inches.
Start converting all the information to the SI.
mass, m = 19 lb * [1kg/2.2046lb] = 8.618 kg
speed: 9.2 ft/s * .3048m/ft = .2.80 m/s
distance to stop: 4.4 in * [2.54cm/in]*[1m/100cm] = 0.11176 m
constant acceleration => Vf^2 = Vo^2 - 2ad
Vf = 0 => a= V0^2 / 2d = [2.80m/s]^2 / (2*0.11176m) = 35.1 m/s^2
Use the second Law of Newton
Net force = m*a = 8.618 kg * 35.1 m/s^2 = 302.5 N
Answer: 302.5 N
