You have been asked to design a \"ballistic spring system\" to measure the speed

Question

You have been asked to design a "ballistic spring system" to measure the speed of bullets. A spring whose spring constant is k is suspended from the ceiling. A block of mass M hangs from the spring. A bullet of mass m is fired vertically upward into the bottom of the block. The spring's maximum compression d is measured.

Here is my issue: I cannot figure out how the heck to get 450 out of this for Part B! I plugged in numbers a bunch of times and never get 450. Please can someone just write out the work of plugging in the numbers that get the correct answer? Maybe draw a diagram or something? Thank you!

Part B ass is 2.1 kg and if the spring, with k 60 hat was the speed of a 12 g bullet if the blocks m Express your answer using two significant figures. vB 450 m/s Submit My Answers Give Up Answer Requested m, was compressed by 48 cm

Explanation / Answer

(m + M)/m = (0.012 + 2.1)/0.012 = 176

2*((m + M)/m)^2*g*d = 2*176^2*9.81*0.48 = 291719.58

((m + M)m^2)*M^2*g^2/k = ((0.012 + 2.1)/0.012^2)*2.1^2*9.81^2/60 = 103742.52

(d - Mg/k)^2 = (0.48 - 2.1*9.81/60)^2 = 0.01867

k*(m+M)*(d - Mg/k)^2/m^2 = 60*(0.012 + 2.1)*0.01867/0.012^2 = 16429.6

Now

Vb = sqrt (291719.58 - 103742.52 + 16429.6) = 452 m/sec

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.