Determine the velocity at which the bullet-block system hits the ground.

In summary, a 0.0020 kg bullet traveling at 300 m/s strikes a 3.0 kg block of wood on a fence post 2.0 m above the ground. Using the equation (m1v1 + m2v2)/Mtotal = 0.2 m/s, the horizontal distance is found by determining the time and using x = v*t. The velocity at which the bullet-block system hits the ground can be found using Vfinal = at + Vinitial, with an included angle. The Pythagorean theorem can also be used to solve for the horizontal and vertical velocities, which is the correct method for solving this problem.
  • #1
tawko
1
0
1. A bullet of mass 0.0020 kg and traveling at 300 m/s strikes the center of a 3.0 kg block of wood which is sitting on a fence post. The block of wood is 2.0 m above the ground.
I got the velocity using the eq (m1v1 + m2v2)/Mtotal = 0.2 m/s [correct if incorrect please]

I then got the horizontal distance by finding time and using x = v*t

Determine the velocity at which the bullet-block system hits the ground. Be sure to include an angle.

2. a^2 + b^2 = c^2 Vfinal = at + Vinitial Xfinal = 1/2at (m1v1 + m2v2) / Mtotal
3. I figured this would involve a right triangle, so I tried solving for the length of the sides. I believe this is where I went wrong. The height of the triangle is 6.272 because i used Vfinal=at+Vinitial, 9.8(.64)+0. I then used the Pythagorean theorem but the answer seemed strange. Thanks.
 
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  • #2
You did it right as far as I can tell, though you don't need the horizontal distance for anything (don't give yourself more work than necessary). By legs of the right triangle, you mean the horizontal velocity and the vertical velocity, right? If so, you're good. :)
 

Related to Determine the velocity at which the bullet-block system hits the ground.

1. What is the formula for determining the velocity at which the bullet-block system hits the ground?

The formula for determining the velocity at which the bullet-block system hits the ground is v = √(2gh), where v is the velocity, g is the acceleration due to gravity, and h is the height from which the system is dropped.

2. How does the mass of the bullet affect the velocity at which the bullet-block system hits the ground?

The mass of the bullet does not affect the velocity at which the bullet-block system hits the ground. The only factors that affect the velocity are the acceleration due to gravity and the height from which the system is dropped.

3. Can the velocity at which the bullet-block system hits the ground be greater than the initial velocity of the bullet?

Yes, the velocity at which the bullet-block system hits the ground can be greater than the initial velocity of the bullet. This can happen if the system is dropped from a height that is greater than the initial height of the bullet.

4. Does air resistance affect the velocity at which the bullet-block system hits the ground?

Yes, air resistance can affect the velocity at which the bullet-block system hits the ground. However, it is usually negligible for small objects like bullets, so it is often ignored in calculations.

5. How can the velocity at which the bullet-block system hits the ground be increased?

The velocity at which the bullet-block system hits the ground can be increased by either increasing the height from which the system is dropped or by increasing the acceleration due to gravity (e.g. by dropping the system on a planet with a higher gravitational pull).

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