8. [-/3 Points] DETAILS SERPSE10 7.4.OP.008.MI. 0/6 Submissions Used MY NOTES ASK YOUR TEACHER The force acting on a particle varies as shown in the figure below. (The x axis in the graph has its tickmarks marked in increments of 0.50 m.) F. (N) 2 C Ex (m) Find the work done by the force on the particle as it moves across the following distances. (a) from x = 0 m to x = 4.00 m J (b) from x = 4.00 m to x = 6.00 m (c) from x = 0 m to x = 6.00 m Need Help? Read It Master It 9. [-/3 Points] DETAILS SERPSE10 7.4.OP.009. 0/6 Submissions Used MY NOTES ASK YOUR TEACHER A light spring obeys Hooke's law. The spring's unstretched length is 33.5 cm. One end of the spring is attached to the top of a doorframe and a weight with mass 7.25 kg is hung from the other end. The final length of the spring is 44.0 cm. (a) Find its spring constant (in N/m). N/m (b) The weight and the spring are taken down. Two people pull in opposite directions on the ends of the spring, each with a force of 180 N. Find the length (in m) of the spring in this situation. m (c) What If? What would be the length (in m) of the spring if it were now attached to the vertical portion of the doorframe and stretched horizontally by a single person exerting a force of 180 N? m Need Help? Read It10. [-13 Points] SERPSE107.4.0P.012. 0/6 Submissions Used ASKYOURTEACHER One end of a light spring with spring constant k1 is attached to the ceiling. A second light spring is attached to the lower end, with spring constant [(2. An object of mass m is attached to the lower end of the second spring. (a) By how much does the pair of springs stretch? (Use the following as necessary: kl, k2, m, and g, the gravitational acceleration.) Xtotal = (b) What is the effective spring constant of the spring system? (Use the following as necessary: k1, k2, m, and g, the gravitational acceleration.) keff = (c) What If? Two identical light springs with spring constant R3 are now individually hung vertically from the ceiling and attached at each end of a symmetric object, such as a rectangular block with uniform mass density. In this case, with the springs next to each other, we describe them as being in parallel. Find the effective spring constant of the pair of springs as a system in this situation in terms of k3. (Use the following as necessary: k3, M, the mass of the symmetric object, and g, the gravitational acceleration.) k eff Need Help? 11. [-I4 Points] DETAILS SERPSE1O 7.4.P.009. 0/6 Submissions Used MY NOTES ASK YOUR TEACHER A particle is subject to a force FX that varies with position as shown in the following figure. 11m 3 (a) Find the work done by the force on the particle as it moves from x = 0 to X = 2.00 m. 5.00 m to X = 9.00 m. (b) Find the work done by the force on the particle as it moves from x :11 (c) Find the work done by the force on the particle as it moves from X = 14.0 m to x = 15.0 m. J H (d) What is the total work done by the force over the distance x = 0 to X = 15.0 m? J H Need Help? _I El 12. [-/1 Points] DETAILS SERPSE10 7.4.P.O12. 0/6 Submissions Used MY NOTES ASK YOUR TEACHER Express the units of the force constant of a spring in SI fundamental units. (Use m for meter, kg for kilogram, and s for second in your equation.) [k] = Need Help? _ 13. [-l6 Points] DETAILS SERPSE10 7.4.P.014. 0/6 Submissions Used MY NOTES ASK YOUR TEACHER A light spring with force constant 3.45 N/m is compressed by 7.40 cm as it is held between a 0.350kg block on the left and a 0.700kg block on the right, both resting on a horizontal surface. The spring exerts a force on each block, tending to push the blocks apart. The blocks are simultaneously released from rest. Find the acceleration with which each block starts to move, given that the coefficient of kinetic friction between each block and the surface is 0, 0.048, and 0.410. (Let the coordinate system be positive to the right and negative to the left. Indicate the direction with the sign of your answer. Assume that the coefficient of static friction is the same as the coefficient of kinetic friction. If the block does not move, enter 0.) (a) I4 = 0 heavier block :] m/s2 lighter block :] m/s2 (b) u = 0.048 heavier block :] m/s2 lighter block :] m/s2 (C) H = 0.410 heavier block :] m/s2 lighter block :] mj's2 Need Help? _