A rifle fires a 2.10 x 10 -2 kg pellet straight upward, because the pellet rests

Question

A rifle fires a 2.10 x 10-2 kg pellet straight upward, because the pellet rests on a compressed spring that is released when the trigger is pulled. The spring has a negligible mass and is compressed by 9.10 x 10-2 m from its unstrained length. The pellet rises to a maximum height of 6.10 m above its position on the compressed spring. Ignoring air resistance and any other friction force, determine the spring constant.

Please be sure the answer is correct this means a lot to my grade this semester and I just can not seem to get it.

Explanation / Answer

the PE of the compressed spring will equal the PE of the object at max height, since at max height it has no vertical velocity

so, PE of a compressed spring = 1/2 kx^2

if the object is a height h above compressed spring, PE at max ht is mgh

equate 1/2 kx^2 = mgh or k=2mgh/x^2

x=9.1010^-2m

m=0.0210kg

g=9.8m/s/s

h=6.10m

substitute and solve for k

K = (2*.0210*9.8*6.10)/(9.10*10^-2)^2 = 303.19

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

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