How does a living cell deal with basic concepts of physics such as length and force? The cell has to measure distances and regulate forces to dynamically organize its interior. This is to a large extent based on microtubules (MTs) and motor proteins. Two concepts are emerging from recent studies as key to the positioning of cell components: preferred disassembly of longer MTs and preferred detachment of motors under high load force. The role of these concepts in nuclear centering and nuclear oscillations is coming to light from experimental and theoretical studies in fission yeast. These universal concepts are likely crucial for a variety of cell processes, including nuclear and mitotic spindle positioning, control of spindle length, and chromosome congression on the metaphase plate.