Final answer:
A nail puller, also known as a claw hammer or pry bar, leverages mechanical advantage to pull nails with less input force. The mechanical advantage is calculated by dividing the input arm length by the output arm length, and a longer handle increases this advantage, applying a greater force to the nail.
Step-by-step explanation:
The tool with a claw at each end commonly used to pull nails is a nail puller, which functions as a lever. A typical nail puller has a large mechanical advantage (MA), which allows a smaller input force to exert a much larger force on the nail being pulled. This mechanical advantage is calculated based on the distances from the pivot point to where the input force is applied and where the output force is exerted on the nail.
The mechanical advantage (MA) is defined as the ratio of the output force exerted by the nail puller (Fo) to the input force applied by the user (F₁). Using the values provided, where the input force is applied at 45 cm from the pivot and the output force at the claw acting on the nail is at 1.8 cm, the MA can be calculated as MA = l₁ / lo. To exert a force of 1250 N on a nail, the minimum force required from the user can be found using the MA and the equation 1₁ F₁ = lo Fo.
The longer the handle on the nail puller, the greater the mechanical advantage and hence, the larger the force you can apply to the nail with less effort. This exemplifies one of the most important concepts in physics and mechanics, where simple machines like the lever can multiply forces and make work easier.