Problem 2 : The only force acting on a 5kg object has components Fx = 15N and Fy = 25N . Find the acceleration of the object .
Solution . m = 5kg Fx = 15N , Fy = 25N F = Fxi + Fyj
= √ 225 + 625 = √850 F = ma Or , a = F / m = √850 / 5 = 5 √34 / 5 = √34 = 5.83m / s 2
Impulse o Impulse is defined as a force multiplied by time it acts over . o
For example : Tennis racket strikes a ball , an impulse is applied to the ball . The racket puts a force on the ball for a short time period .
F ∆t = ∆p F = ∆p / ∆t = Rate of Change of momentum