A 4.50-kg experimental cart undergoes an acceleration in a straight line (the x -axis). The graph in ?Fig. E4.13? shows this acceleration as a function of time. (a) Find the maximum net force on this cart. When does this maximum force occur? (b) During what times is the net force on the cart a constant? (c) When is the net force equal to zero?

Solution 13E Step 1: 2 a) The maximum acceleration of the cart from the graph, a = 10 m/s Mass of the cart, m = 4.50 kg We know that, the force, F = ma F = 4.50 kg × 10 m/s = 45 kgm/s = 45 N This maximum force will occur when time, t = 2.0 s Step 2: b) From t 1 2.0 s to t = 2.0 s, the force will be a constant as per the graph since, the acceleration is constant there.