CHAPTER 9 9-7 Work and Kinetic Energy 9.4 Restoring Forces and the Work Done by a Spring 19. A spring is attached to the floor and pulled straight up by a string. The string's tension is measured. The graph shows the tension in the string as a function of the spring's length L. T(N) Tension T 10 5 L L (cm) 10 a. Does this spring obey Hooke's Law? Explain why or why not. 58 w.Huc dot 112RK b. If it does, what is the spring constant? 20. Draw a figure analogous to Figure 9.17 in the textbook for a spring that is attached to a wall on the right end. Use the figure to show that F and As always have opposite signs. 20

the potential energy of a particle is given by U(x)= (9 J/m^4)x^4-(8 J/m^2)x^2.  At what value of x would the particle be in unstable equilibrium? A.) -2/3 m B.) sqrt of 8/9 m c.) 0 m d.) 2/3 m e.) sqrt of - 8/9 m

You are loading a toy dart gun, which has two settings, the more powerful with the spring compressed twice as far as the lower setting. If it takes 5.0 J of work to compress the dart gun to the lower setting, how much work does it take for the higher setting?  a. 20 J b. 10 J c. 2.5 J d. 40 J

7. DETAILS MY NOTES A toy cannon uses a spring to project a 5.28-g soft rubber ball. The spring is originally compressed by 4.90 cm and has a force constant of 8.01 N/m. When the cannon is fired, the ball moves 15.9 cm through the horizontal barrel of the cannon, and the barrel exerts a constant friction force of 0.032 3 N on the ball. ASK YOUR TEACHER (a) With what speed does the projectile leave the barrel of the cannon? m/s (b) At what point does the ball have maximum speed? cm (from its original position) (c) What is this maximum speed? m/s

A child has two red wagons, with the rear one tied to the front by a stretchy rope (a spring). If the child pulls on the front wagon, the ____ increases. a. kinetic energy of the wagons b. potential energy stored in the spring c. both A and B d. not enough information

Question 6 When a student stretches a spring, what is the flow of energy? a. Energy goes into the spring and into the student. X b. There is no change in the energy of the spring, only for the student. c. There is no change in the energy of the student, but there is a change for the spring. d. Envery leaves the spring and goes to the student. e. Energy goes into the spring from the student.

Work and energy

5. A 0.085kg toy popper, the plastic kind made from a spring and a suction cup, is compressed 0.03m towards the tabletop. It releases and "pops" up to a maximum height of 0.35m above the tabletop. a. What is the potential energy at its highest point? b. What was the kinetic energy when it left the tabletop? c. How fast was it moving when it left the tabletop? d. How much elastic potential energy was in the popper spring when it was compressed? e. What is the spring constant of the spring in the popper?

need help with A-f

I. General setup - 0.5 m Object of known size (e.g., piece of paper) String Nut / Object II. Prediction questions and background physics For this experiment, you will release the object from rest and observe its subsequent motion. Before conducting the experiment or doing your analysis, answer the following questions based on your understanding of the physics of motion and conservation of energy: