Calculate Arrow Velocity from Stored Energy

  • Thread starter Thread starter KingBigness
  • Start date Start date
  • Tags Tags
    Energy Velocity
AI Thread Summary
To calculate the velocity of a 15 gm arrow leaving the bow, first determine the kinetic energy transferred to the arrow, which is 64% of the stored energy of 305 mJ, resulting in 195.2 mJ. Using the kinetic energy formula, 0.5 * m * v^2, where m is the mass in kg (0.015 kg), the equation becomes 195.2 mJ = 0.5 * 0.015 * v^2. Rearranging the equation allows for solving v, leading to a calculated velocity of approximately 73.4 m/s. This demonstrates the application of conservation of energy principles in determining arrow velocity.
KingBigness
Messages
94
Reaction score
0

Homework Statement



If the extension of the bow is 5.5 cm and you have determined that this corresponds to 305 mJ , what is the velocity with which a 15 gm arrow will leave the bow if 64 percent of the stored energy is transferred to the arrow?
Calculate the velocity in m/s but do not include the units in your answer.


Homework Equations



none

Please help!
 
Physics news on Phys.org
KingBigness said:

Homework Statement



If the extension of the bow is 5.5 cm and you have determined that this corresponds to 305 mJ , what is the velocity with which a 15 gm arrow will leave the bow if 64 percent of the stored energy is transferred to the arrow?
Calculate the velocity in m/s but do not include the units in your answer.


Homework Equations



none

Please help!

This is a problem in the conservation of energy. The potential energy stored in the bow ends up as kinetic energy of the arrow (or, in this case, 64% of it ends up as kinetic energy of the arrow).

So what is the kinetic energy of the arrow?

Do you see how to use the mass and the energy to find the velocity of the arrow? (Be careful to keep units consistent.)
 
So can i use FD=0.64(1/2mv^2)
 
wait...thats not right...0.64FD=1/2mv^2?
 
KingBigness said:
wait...thats not right...0.64FD=1/2mv^2?

That'll do it.
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top