Final answer:
The minimum up-thrust force is equal to the weight of the water displaced by the float, while the maximum up-thrust force is equal to the weight of the float itself. Strain gauges can be used to monitor the deformation of the beam under the force of the up-thrust.
Step-by-step explanation:
The minimum up-thrust force exerted by the float on the beam occurs when the float is fully submerged. In this case, the up-thrust force is equal to the weight of the water displaced by the float. The maximum up-thrust force occurs when the float is floating at the water surface. In this case, the up-thrust force is equal to the weight of the float itself.
To monitor the deformation of the beam under the action of the up-thrust force, strain gauges can be used. Strain gauges are devices that measure the strain or deformation of a material. By attaching strain gauges to the beam, any changes in the beam's shape or size due to the up-thrust force can be detected and measured.