phET 2D Collision Lab by Hugo

phET 2D Collision Lab

To investigate the conservation of momentum and kinetic energy in

two-dimensional collision using a simulation

Student name: Hugo. Cui

Date Oct 21st, 2015 Abstract

The purpose of this lab was to use two balls collide each other in 1D and 2D, and the situation of elastic and inelastic. During the experiment, the angle effect the result of collision too but in the X and Y component the result doesn’t change. The absolute value of momentum between those two balls doesn’t chang e any more. But the relationships between vectors of every cases is different.

introduction

The purpose of this lab is to investigate the conservation of momentum and kinetic energy in two-dimensional collisions using a simulation.there are four different collisions which are 1D and 2D in elastic and inelastic. Before the lab three hypothesis statement that should be found out :1the changes in total kinetic energy of a system during collision. 2 the changes in total momentum of a system during collision. 3 the effect of elasticity on kinetic energy and momentum. Before the lab, the important background information are two function momentum=M times V. And the function of the kinetic energy is Ke=1/2MVpower of 2.

Materials and Apparatus

Materials:

Computer

Ruler or protractor

Calculator

Tool in https://www.wendangku.net/doc/91103047.html,/sims/collision-lab/collision-lab_en.html Apparatus:

NO

Note: because most step of lab do in the computer and there is no handout so conclude the data into a table include the velocity vector mass and momentum.

Procedure

1)Enter the website:

https://www.wendangku.net/doc/91103047.html,/sims/collision-lab/collision-lab_en.html

2)Choose the advanced tab menu, select 1 dimensions, velocity vectors, show path, and show values.

3)Use cursor to move the elasticity slider at the bottom of the menu

to(elasticity 100%). This collision will be between an object moving horizontally and an object at rest. Set the velocities.

4)Record the mass and the initial and final velocities of each ball in a data table.

5)In the advanced tab menu ,select 2dimensions.

6)Adjust the angle and initial velocities of the balls.

7)Record all initial and final data for the trial.

8)In the advanced tab menu, select 1dimensions.

9)Adjust the elasticity slider to(elasticity 0%).

10)Record all initial and final date for the trial.

11)In the advanced tab menu, select 2 dimensions.

12)Adjust the angle and initial velocities of the ball.

13)Record all initial and final data for the trial. Observations

Ball1 0.9kg Ball2 1.5kg Speed1 0.00 Speed1 1.30 Speed2 1.62 Speed2 0.32 Momentum1 0.00 Momentum1 1.94 Momentum2 1.46 Momentum2 0.49

Ball1 0.9 Ball2

1.5 Speed1 0.99 Speed1 1.30 Speed2 1.76 Speed2 0.66 Speed3 1.34 Speed3 1.10 Momentum1 0.89 Momentum1 1.95 Momentum2 1.58 Momentum2 0.98 Momentum3

1.21

Momentum3

1.64

Ball1 0.9 Ball2 1.5 Speed1 1.20 Speed1 0.00 Speed2 0.45 Speed2 0.45 Momentum1 1.08 Momentum1 0.00 Momentum2

0.40

Momentum2

0.67

Ball1 0.9 Ball2 1.5

Speed1 1.36 Speed1 1.09

Speed2 0.55 Speed2 0.27

Speed3 0.00 Speed3 0.00 Momentum1 1.23 Momentum1 1.64 Momentum2 0.49 Momentum2 0.41 Momentum3 0.00 Momentum3 0.00

Discussion

Based on the data in four tables above, the speed and momentum before and after collision were given. However in the graph the direction of the ball decides the negative and positive, so in the table data are absolute number.

1)Change in total kinetic energy of a system during collision

In the elastic collision, kinetic energy doesn’t change. Because the function K e=1/2MV2 , however in elastic collision the V just exchange to another ball, and the M is constant. On the other hands in inelastic collision the V become to 0 after collide each. So K e change to decreasing.

2)Change in total momentum of a system during collision

Weather elastic or inelastic collision, momentum doesn’t change of all, momentum=M1V1+M2V2 but direction depend the negative and positive.

So the sum didn’t change.

3)The effect of elasticity on kinetic energy and momentum. Elasticity will effect kinetic energy but not momentum.

Error analysis

Human: input wrong data into the lab or the measure problem. Others: website tool makes something wrong.

Conclusion

The momentum is conservation is true. However kinetic energy is effected by elasticity. Ke is conservation that is elastic collision, or is decrease in inelastic.