A 4.0-m-long, 500 kg steel beam extends horizontally from the point where it has been bolted to the framework of a new building under construction. A 70 kg construction worker stands at the far end of the beam. What is the magnitude of the torque about the bolt due to the worker and the weight of the beam?
Effect of molecular shape on electric forces (solution) 4.2.4.P11 The electric attractions and repulsions of the ions on the surface of co mplex molecules play a critical role in many biochemical reactions. An i nteresting component of some of these processes is that chemical reactions or elec tron transfers result in a change of the shape of a molecule, exchanging chemical energy for electrical energy, and resulting in a different surface configurati on and therefore different interactions. In this problem we will explore the effect of a change of configuration of a molecule on the force between it and an ion in a neighboring molecule. Consider the electric force between four ions on the surface of two larg e molecules as shown in the figure at the right. The heavy bl