A 98.0 N grocery cart is pushed 12.0 m along an aisle by a shopper who exerts a constant horizontal foce of 40.0 N. If all frictional forces are neglected and the cart starts from rest, what is the grocery cart's final speed?
As the acceleration of gravity g = 9.8 m/s^2, then the mass of cart is m = 98/9,8 = 10 kg. Using the Newton's Second Law F = ma. So, the cart's acceleration is a = F/m = 40/10 = 4 m/s^2. As the initial speed was zero, we get the equation for displacement and final speed: S = a*t^2/2, V = at. t = sqrt(2*S/a). V = a*sqrt(2*S/a) = sqrt(2*S*a) = sqrt(2*12*4) = sqrt(96) = 9.8 m/s.