Perfectly Inelastic and initial kinetic energy

In summary, when an object of mass m collides with a target object of mass 2m, the collision results in a perfectly inelastic collision. This means that the final kinetic energy is equal to 1/3 of the initial kinetic energy.
  • #1
jan2905
41
0
An object of mass m (O1) moving with speed v collides head-on with a target object of mass 2m (O2) initially at rest. If the collision is perfectly inelastic, what fraction of O1's initial kinetic energy is lost?



1/2(m1)v^2initial=1/2(m1+m2)v^2final

m1v1=(m+2m)v2

v2=1/3(v1)

so...

1/2(m1)v^2=1/2(m1+m2)(1/3*v)^2 ... is this right so far?
 
Physics news on Phys.org
  • #2
Take the ratio of the final kinetic energy to the initial kinetic energy. These two are not equal to each other unless you include a ratio factor on the left side of the equation.
 
  • #3
1/3? 3m*(1/9)v^2 yields a factor of 1/3.
 
  • #4
Correct.
 

FAQ: Perfectly Inelastic and initial kinetic energy

1. What is perfectly inelastic collision?

Perfectly inelastic collision is a type of collision where two objects collide and stick together, becoming one object. This means that after the collision, the objects move together with the same velocity.

2. How is initial kinetic energy related to perfectly inelastic collision?

In perfectly inelastic collision, the initial kinetic energy of the system is not conserved. This means that the total kinetic energy of the system before the collision is different from the total kinetic energy after the collision. Some of the initial kinetic energy is converted into other forms of energy, such as heat and sound.

3. What happens to the momentum in a perfectly inelastic collision?

In a perfectly inelastic collision, the total momentum of the system is conserved. This means that the total momentum before the collision is equal to the total momentum after the collision. However, the individual momenta of the objects may change due to the objects sticking together.

4. How does the coefficient of restitution relate to perfectly inelastic collision?

The coefficient of restitution is a measure of the elasticity of a collision. In perfectly inelastic collision, the coefficient of restitution is equal to 0, meaning that the objects do not bounce off each other and stick together instead.

5. Can perfectly inelastic collision occur in real-life situations?

Yes, perfectly inelastic collision can occur in real-life situations. Examples include two cars colliding and sticking together, a bullet hitting a block of wood and getting embedded in it, or two drops of water combining into one larger drop upon collision.

Back
Top