Shm

Question 1

How to measure MOVING MOTION displacment Against time
- so like a pendulum or spring moving SHM

1) stroboscope

Answer 1

Use a STROBOSCOPE of known frequency
- photograph it so that several pictures appear on one image image
-then can measure displacement if the scale is on the image, measuring from centre

For the time, you know the frewuency if the stroboscope, so you know the time BETWEEN PICTURES

Question 2

How to measure MOVING MOTION displacment
- so like a pendulum or spring moving SHM

2) using a camera!
(What camera is better)

Answer 2

Must use a camera with FREEZE FRAME FACILITY, or slow motion
- take pictures / video
- if video you know the time between
- if using pictures make sure you know the frequency of pictures taken so you can work out time

Then with a scale in the pictures to find displacment you can plot it against time

2) better to use freeze frame compared to slow motion for markschemes

Question 3

2 CONSIDERATIONS that need to do which can affect readings if displacment when usign stroboscope or slow motion/ freeze from camera?

Answer 3

1) ensure the scale is as close to camera as possible to REDUCE PARALAX ERROR
2) ensure camera is aligned 90° to oscillation POIMT to reduce parallax error

Question 4

What does stroboscope do

Answer 4

It flashes light at frequencies which makes us see it as stationary due to eye lag

This way we can measure the displacements as if they were froze in time

Question 5

How do we take pictures using stroboscope ? On same image?

Question 6

Stroboscope

Answer 6

Question 7

Accuracy from camera (reduce parallax and accuracy increas)?

Answer 7

Ensure distance scale close to mass to reduce parallax, and move the camera with the ball to reduce parallax, and aim the camera 90°