I just need help with the last few answers. i\'m not sure how to calculate them
ID: 1649913 • Letter: I
Question
I just need help with the last few answers. i'm not sure how to calculate them
Run the simulation below: (if the simulation doesn't display below, go to this link http://phet.colorado.edu/sims/collision-lab/collision-lab_en.html
Instructions `
Click “1 Dimension” at the top.
Drag the green ball all the way to the right. Observe the “X”
What does the X represent? It represents the center of mass.
Which ball must be more massive? It would have to be the green ball.
How do you know (other than the fact that it tells you at the bottom) The X lies closer to the green than the red, indicating the center of mass tilts toward the more “massive” object.
What happened that made the X change direction? The two objects changed direction because they collided and therefore, were forced in opposite directions.
If the velocity of X is supposed to be constant for any system, then why does speed and direction change? Velocity changes because there are two objects involved with different masses and according to Newton’s First Law, all objects will remain in motion (in this case) with the same speed and direction unless acted upon by an unbalanced force.
Reset the animation. Click 1 Dimensional again. Click the button that says “More Data”
Drag the red ball all the way to the left, and the green ball all the way to the right.
Hit Play, but Hit Pause before the balls collide.
If you were an observer on the red ball, what would the velocity of green ball be relative to you (include a direction)? The green ball’s velocity is half that of the red ball. It travels half the distance that the red ball does.
If you were an observer on the green ball, what would the velocity of red ball be relative to you (include a direction)? The velocity of the red ball is half that of the green ball. It travels double the distance that the green ball does.
For all Calculations, Show Your Work. Used the data to check yourself.
Calculate:
Momentum of mass equation: p = mv
The initial momentum of mass 1: 0.5 * 1 = 0.5 kg m/s
The initial momentum of mass 2: 1.5 * -0.5 = -0.750 kg m/s
Total initial momentum: 0.5 - 0.75 = -0.25 kg m/s
The initial kinetic energy of mass 1: 0.5 * 0.5 * 1^2 = 0.25 J
The initial kinetic energy of mass 2: 0.5 * 1.5 * 0.5^2 = 0.19 J
Total initial kinetic energy: 0.25 + 0.19 = 0.44 J
Hit play again, but hit pause immediately after the collision (don’t allow a ball to hit a wall)
Calculate:
The final momentum of mass 1: 0.5 * -1.25 = -0.75 kg m/s
The final momentum of mass 2: 1.5 * 0.25 = 0.35 kg m/s
Total final momentum: -0.625 - 0.375 = -0.975 kg m/s
The final kinetic energy of mass 1: 0.5 * 0.5 * 1.25^2 = 0.4 J
The final kinetic energy of mass 2: 0.5 * 1.5 * 0.25^2= 0.04 J
Total final kinetic energy: 0.4 + 0.04 = 0.44 J
What can you conclude about the momenta and kinetic energies of the system?
The total kinetic energy stayed constant because in this type of collision, the total energy is conserved. The X momentum increased in the negative direction.
What type of collision is this : It is called a perfect elastic head-on collision.
Reset, select 1 Dimension again, and set the elasticity = .50
Hit play and pause before and immediately after the collision (don’t allow a ball to hit a wall)
Calculate:
The initial momentum of mass 1: 0.5 * 1 = 0.5 kg m/s
The initial momentum of mass 2: 1.5 * -0.5 = -0.750 kg m/s
Total initial momentum: 0.5 - 0.750 = -0.25 kg m/s
The initial kinetic energy of mass 1: 0.5 * 0.5 * 1^2 = 0.25 J
The initial kinetic energy of mass 2: 1.5 * -0.75 = -1.125 J
Total initial kinetic energy: 0.25 + -1.125 = -875 J
The final momentum of mass 1: 0.5 * 0.7 * -0.35 ^2 = 0.25 kg m/s
The final momentum of mass 2: 1.5 * 0.06 * 0.1= 0.0009 kg m/s
Total final momentum: 0.25 + 0.0009 = 0.25 kg m/s
The final kinetic energy of mass 1: _____________________________________
The final kinetic energy of mass 2: _____________________________________
Total final kinetic energy: ____________________________________________
What can you conclude about the momenta and kinetic energies of the system? __________________________________________________________________
What type of collision is this : _______________________
Explanation / Answer
Initial momentum of mass 1 is 0.5*1 = 0.5 kg m/sec
initial momentum of mass 2 is 1.5*0 = 0 kg m/sec
the total initial momentum is 0.5+0 = 0.5 kg m/sec
the initial kinetic energy of mass 1 is 0.5^2/(2*0.5) = 0.25 J
the initial kinetic energy of mass 2 is 0^2/(2*1.5) = 0 J
total initial kinetic energy is 0.25+0 = 0.25 J
the final momentum of mass 1 is -0.5*0.13 = -0.06 kg m/sec
the final momentum of mass 2 is 1.5*0.38 = 0.56 kg m/sec
total final momentum is -0.06+0.56 = 0.5 kg m/sec
the final kinetic energy of mass 1 is 0.06^2/(2*0.5) = 0.0036 J
the final kinetic energy of mass 2 is 0.56^2/(2*1.5) = 0.104 J
total final kinetic energy is 0.0036+0.104 = 0.1076 J
what can you conclude anout momenta and kinetic energies of the system
only law of conservsation of momenta is obeyed but not law of conservation of kinetic energy.i.e total initial mometum is equal to the total final momentum and
total initial kinetic energy is not equal to the total final kinetic energy
what type of collision is this
since only law of conservsation of momenta is obeyed but not law of conservation of kinetic energy.
hence the collision is inelastic collision