Questions 101020

#$&*

course Phy 241

October 25 around 10:45pm.

LAB 101020Acceleration vs. Ramp Slope

Using the TIMER program, time a ball down the steel ramp when the ramp is supported by a single domino lying flat. Do five trials with this setup.

Report the median time, the distance the ball traveled from rest in this time, and the resulting acceleration.

****

1.76 sec, 30cm, 19.37cm/s^2

[used (‘ds=0.5a’dt^2) to find my accelerations]

#$&*

Report the rise and run between two points of the ramp and the resulting slope.

****

Rise: 0.6cm (domino only)

Run: 30cm (length of ramp)

Slope: 0.6/30=0.02

#$&*

Repeat with the domino lying on its long edge, so that the rise is equal to the width of the domino. Do five trials with this setup.

Report the median time, the distance the ball traveled from rest in this time, and the resulting acceleration.

****

1.016 sec, 30cm, 58.125cm/s^2

#$&*

Report the rise and run between two points of the ramp and the resulting slope.

****

Rise: 2.4cm (domino’s width)

Run: 30cm (length of ramp)

Slope: 2.4/30=0.08

#$&*

Based on these two setups, at what rate does the acceleration of the ball appear to change with respect to ramp slope?

****

Acceleration/slope

1st trial: (19.37cm/s^2)/0.02=968.5cm/s^2

2nd trial: (58.125cm/s^2)/0.08=726.5cm/s^2

968.5-726.5=242cm/s^2

You haven't yet applied the definition correctly. You do have the right information, so give it another try.

#$&*

Now time the toy car down the wood ramp, using two different slopes. Be sure the ramp is straight. Suggestion: Use your textbook to help. Support it at one end with something reasonably rigid, whose thickness you can measure with good accuracy (for example a couple of CD or DVD cases would be a good choice, using one for the first setup, and both for the second). Using one hand hold the wood piece flat against the book, release the car with another hand, and operate the TIMER with your third hand. If you don't have three hands, adapt the suggestions accordingly. You might also find it helpful to use the steel ramp to press the wood ramp against the book.

For the first slope:

Report the median time, the distance the ball traveled from rest in this time, and the resulting acceleration.

****

1.265sec, 40cm, 50cm/s^2

[raised the board up with 2 dominos and leveled it out by putting one domino underneath the middle of the board]

#$&*

Report the rise and run between two points of the ramp and the resulting slope.

****

Rise: 2.1cm (dominos + board width)

Run: 40cm (length of board)

Slope: 2.1/40=0.0525

#$&*

For the second slope:

Report the median time, the distance the ball traveled from rest in this time, and the resulting acceleration.

****

0.891sec, 40cm, 100.8cm/s^2

[raised the board up with 3 dominos this time and still used a domino underneath the board to level it out and make it straight]

#$&*

Report the rise and run between two points of the ramp and the resulting slope.

****

Rise: 3.1cm (dominos + width of board)

Run: 40cm (length of board)

Slope: 3.1/40=0.0775

#$&*

Based on these two setups, at what rate does the acceleration of the ball appear to change with respect to ramp slope?

****

Acceleration/slope

1st trial: (50 cm/s^2)/0.0525=952.38cm/s^2

2nd trial: (100.8cm/s^2)/0.0775=1300.65cm/s^2

1300.65-952.38=348.3cm/s^2

#$&*

Is acceleration independent of position and velocity?

You were asked previously to design an experiment to test whether acceleration is independent of position and velocity, on a ramp with constant incline.

Do a 30-minute preliminary run, using the TIMER. Just take whatever data you can in 15 or 20 minutes, and give a brief report of your setup, your data and your results. Try to be as accurate as possible within the 15-20 minute time constraint.

****

What I did was use my 30cm ramp, set up 3 different slopes, using 1 domino, then 2 dominos, and then 3 dominos. I set a meter stick right beside of the inclined ramp and taped it to the side of the ramp so it would be accurate measurements. I then did 3 trials for the ball going down the entire ramp (30cm) and then did 3 trials on the ball going to the midpoint (15cm mark) and used the TIMER to see the times it took, according to the slopes I used. Here are my results:

1 domino (approx. 1cm thick):

(30cm) 1.578, 1.64, 1.562

(15cm) 0.844, 0.844, 0.859

2 dominos (approx. 2cm)

(30cm) 0.968, 1.015, 0.937

(15cm) 0.531, 0.64, 0.5

3 dominos (approx. 3cm)

(30cm) 0.828, 0.844, 0.813

(15cm) 0.484, 0.460, 0.422

According to my data and results, acceleration is independent of position and velocity.

you haven't reported any accelerations in this part, so it's not clear that your conclusions follow from your data

You're just about there, but you need a couple of modifications.

&#Please see my notes and submit a copy of this document with revisions and/or questions, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end).

Be sure to include the entire document, including my notes.

&#

#$&*