An engineer is testing a prototype cable-delivery system on a horizontal test track, as shown in the diagram below.
A cart on the horizontal track is connected by a light, inextensible string passing over a smooth pulley to a suspended mass carrier. To investigate how the acceleration of the cart depends on the pulling force, several identical metal blocks are placed on top of the cart.
Describe how the engineer can increase the accelerating force acting on the system while keeping the total mass of the system constant.