Question

hammering nails - physics PROBLEM: When removing a nail, where should you hold a hammer to use the least amount of effort force? Your lab must be written up in "standard lab format". Refer to the "How to Write Up a Lab" document found under the Unit 2 Resources link for instructions on how to do this. (Note: Percent error calculations are not required for this lab.) Procedure: 1) Hammer two identical nails into a piece of wood so that the heads are slightly above the wood. 2) Wedge the jaws of the hammer beneath the head of the first nail and hold the handle close to the head of the hammer. 3) Before removing the nail, measure the resistance distance, the position of the fulcrum and the effort distance. 4) Remove the nail…take a digital picture of yourself doing this step. 5) Note the amount of effort force necessary to remove the first nail. 6) Repeat the process for the second nail, but hold the head of the handle as you remove the second nail. Again, take a digital picture. Calculations: Calculate the mechanical advantage of the hammer for each nail. Conclusion Questions: a) Where should you hold the hammer to ensure the greatest mechanical advantage? Explain your answer. b) Explain why simple machines, such as hammers pulling nails, are able to reduce the effort force.

Answer 1

The mechanical advantage will be the ratio of the force applied to the force required to remove the nail.

a] The hammer must be held at its handle (maximum distance from the nail) to get greatest mechanical advantage. This means that the required force to remove the nail becomes less in the 2nd case.

b] The applied force essentially creates a turning effect. This creates an opposite upward force on the nail which moves it upwards. The turning effect created (torque) is a product of force applied and the distance of its application from the fulcrum. In this 2nd case, the distance of the application of force is increased by using the handle and so a larger turning effect is generated by a small force. Therefore this reduces the effort force.