<span>they are travelling at right angles to each other. At any given instant they form a right triangle with their starting point </span>South bound <span>= x [mi/h] </span> East bound <span> = x+1 [mi/h] after five hours they will be d=5x and d=5(x+1) miles away from the starting point (5x)^2+(5(x+1))^2=625 25x^2+(5x+5)^2=625 25x^2+25x^2+50x+25=625 50</span>x^2+50x-600=0 <span> x^2+ x - 12=0 (x+4)(x-3)=0 take the postive value x= 3 mph the speed of south bound 4mph east bound </span>
Work is calculated by multiplying force by the distance that the object had moved. The applied force is 60 N, moving the object by 10 m. Thus, the work does is 600 J. For the friction force which is equal to, 100N x 0.250 = 25.0 N the work done is, W = (60 N - 25 N) x 10 m = 350 J The kinetic energy of the box can be equated to this force. Thus, the answer is also 350 J.
