The unstretched length of spring AB is 3.4 m. If the block is held in the equilibrium position shown, determine the mass of the block at D. (Figure 1) Submit Previous Answers Correct Part B Determine the mass of the block at D. Express your answer to three significant figures and include the appropriate units. Figure 3m 4 m ? m = 7.88 kg KAC = 20 N/m KAB - 30 N/m Submit Previous Answers Request Answer KAD = 40 N/m X Incorrect; Try Again; 2 attempts remaining Provide FeedbackLearning Goal: To understand how to construct a free-body diagram for an object that can be treated as a particle. i The free-body diagram is a fundamental tool used in engineering mechanics. It is simply a sketch that shows the particle "free" from its surroundings with all forces that act on the particle. By correctly constructing a free-body diagram, one can account for all of the forces in the No elements selected equations of equilibrium. It is often helpful to draw an enclosing circle (or loop) around the object(s) of interest and account for (a) forces in cables cut by the circle, (b) reaction forces between the object and any supports at the boundary of the circle, and (c) the weight of the object(s) B TCB enclosed by the circle. E I BA TCE AT DC Figure B Select the elements from the list and add them to the canvas setting the appropriate attributes. Submit Previous Answers X Incorrect; Try Again; 3 attempts remaining