Tell me how fast I shot it!

Classical Mechanics Level 3

An archer pulls back 0.75 m on a bow which has a stiffness of 200 N/m. The arrow weighs 50 g. What is the velocity of the arrow immediately after release?

The answer is 47.4.

3 solutions

Mardokay Mosazghi
Jun 1, 2014

The bow can be treated as a type of spring. The potential energy of a spring is: PE = (1/2)(200)(0.75)2 = 56.25 J assuming that this like a spring.Then lets calculate the kinetic energy of a particle is (1/2)mv^2 so it is KE = (1/2)(0.05)v2 not let the make the assumption that energy is conserved, then PE = KE Solving for v we get 47.4 m/s

Dude you know archery is my best/favorite sport? You could have submitted this for TPC 5. Actually, you still can. Great problem! :D

Finn Hulse - 7 years ago

What is tpc 5 @Finn Hulse

Mardokay Mosazghi - 7 years ago

Themed Problem Challenge.

Finn Hulse - 7 years ago

@Finn Hulse – Do you want me to put the link

Mardokay Mosazghi - 7 years ago

@Mardokay Mosazghi – First you'd better clean up your problem and solution with $\LaTeX$ . And remember it has to be Finn-themed.

Finn Hulse - 7 years ago

Mohd Naim Mohd Amin
Jun 19, 2014

Hello,

By using the principle conservation of energy,

Ei = Ef , as Ei = elastic potential energy, Ef = kinetic energy ,

0.5(k)(x)^2 = 0.5(m)(v)^2

kx^2 = mv^2

v^2 = kx^2 / m

v = [ (200)(0.75)^2 / 0.05 ]^ 0.5 = 47.434 m/s....

Ishan Dixit
Jun 18, 2014

Such a kiddo problem

can u plz upload some good questions.

Ishan Dixit - 6 years, 12 months ago

@Ishan Dixit I am so sorry I didnot have time to post good questions but now i will start this week follow me.

Mardokay Mosazghi - 6 years, 11 months ago

Tell me how fast I shot it!

The answer is 47.4.

3 solutions

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