Homework answers / question archive / You have been asked to design an experiment to measure the speed of a ?red bullet as part of your new job in the military sector

You have been asked to design an experiment to measure the speed of a ?red bullet as part of your new job in the military sector

Physics

Share With

You have been asked to design an experiment to measure the speed of a ?red bullet as part of your new job in the military sector. You decide you will use your knowledge of springs, conservation of momentum and energy to design your experiment. You decide to hang a spring with constant k vertically and attach a block of mass M to the end of the spring. The bullet of mass m is then ?red vertically upward into the wooden block where it embeds into the block. You will measure the distance d that the spring is compressed and use this to ?nd the initial speed of the bullet.

A. a Place the origin of your coordinate system on equilibrium position of the unstretched spring. Draw a before and after diagram of the bullet—spring system. Be sure to label any speeds, changes in length of the spring, and important information about the problem. Label the unknown buliet's speed 173. Label the unknown speed of the bullet + block system after the bullet embeds 110.

B. Determine the symbolic energy conservation equation for the system when the bullet is just embedded in the block and later when the spring is at its maximum compression.

C. Determine the momentum conservation equation for the bullet-block system. Find the speed 120 of the bullet-block system just after the bullet embeds in the block in terms of the masses m and M of the bullet and block and the unknown speed of the bullet v3.

D. Using your equations from part B and C, determine the initial speed VB of the bullet. Your expression should only be in terms of the given variables in the problem statement and the acceleration due to gravity: m, M, k, d and g.

E. Asses the validity of your expression using at least two sense-making techniques we have learned in class.