(a)[1]
State what work done means.
(b)[2]
A trolley with mass $400\,\text{g}$ travels at a steady speed of $2.5\,\text{m s}^{-1}$ to the right, as shown in Fig. 3.1. Show that the trolley's kinetic energy is $1.3\,\text{J}$.
(c)[5]
In (b), the trolley moves to point P as shown in Fig. 3.2. At P, its speed is $2.5\,\text{m s}^{-1}$. A variable force $F$ acts to the left on the trolley while it travels from P to Q. Figure 3.3 shows how $F$ changes with displacement $x$ measured from P. The trolley is at rest at Q. (i) Calculate the distance PQ. (ii) On Fig. 3.4, sketch how velocity $v$ varies with $x$ for the trolley moving from P to Q.