Resolution of a Force Lab (quicky lab today, groups of two, worth 10 pts.)
Einstein Board
1. Students drew the largest right triangle they could on an Etch-a-Sketch board. Noting the hypotenuse...when you turned the dials to draw the hypotenuse you turned the vertical dial the exact same amount as the vertical leg of the right triangle and you turned the horizontal dial the exact same amount as the horizontal leg of the hypotenuse....thus a diagonal vector can be resolved into a right triangle with a horizontal & vertical component. These horizontal and vertical components are hidden in the hypotenuse.
2. Explanation of the Resolution of Force Quickie Lab
3. Students completed the lab and handed it in (Groups of Two or Three)
If you missed today find a Physics student who has done the lab and complete the lab ASAP. The materials for the lab and the handout are in back of the Physics room next door.
The Resolution of a Force (Boom Lab) version 1 or version 2 we did version 2 in class.
Notes from 2012 but always relevant to the Resolution of a Force Lab
Note in the resolution of a force lab above a spring scale is hanging over a cabinent attached to a C clamp on the cabinent. A string is wrapped around the eye screw at the end of a special springy stick (called a boom) so that a weight can be suspected from the end of the stick by held out away from the cabinent by the boom. This setup makes a right triangle with one leg being the boom stick, one leg being the cabinent, and the hypotenuse the spring scale. If you read the cm on the boom stick and simply record for now and the force F on the spring scale and measure the angle in one of many ways by the eyescrew you can use SOHCAHTOA to calculate the legs of the hypotenuse.
The adjacent boom leg would be FcosA and the cabinent leg would be FsinA.
Now you measure the actual weight of the hanging weight by simply hanging it from an appropriate spring scale and get the much harder reading of the boom force by attaching your spring scale to the eyescrew at the end of the boom and pulling it to the same cm reading you recorded above and have your partner read the spring scale.
The Big Picture:
1. Remember the etch-a-sketch when you drew a right triangel? The hypotenuse was made by turning a vertical knob and horizontal knob only. The exact amount of times you turned the horizontal knob equals the amount of times you turned it to draw the horizontal leg of your right triangle. The exact amount of times you turned the vertical knob to draw the hypotenuse equals the amount of times you turned it to draw the vertical leg of your right triangle. Thus the hypotenuse has the vertical and horizontal legs hidden in it allowing you replace the hypotenuse reading with the vertical and horizontal legs which have more meaning to us humans.
2. The force of the weight hanging down then equals the vertical leg (cabinent, FsinA) and the boom leg (FcosA) equals the force it took to pull against the string in the boom. Both of these are hidden in your hypotenuse reading.
3. Note that the legs are two vectors added tail to head (the boom direction into the boom and the cabinent leg up as it was holding the weight pulling down) and the scale reading hypotenuse is the resultant of these two vectors.
COOL HEY!
Note in the resolution of a force lab above a spring scale is hanging over a cabinent attached to a C clamp on the cabinent. A string is wrapped around the eye screw at the end of a special springy stick (called a boom) so that a weight can be suspected from the end of the stick by held out away from the cabinent by the boom. This setup makes a right triangle with one leg being the boom stick, one leg being the cabinent, and the hypotenuse the spring scale. If you read the cm on the boom stick and simply record for now and the force F on the spring scale and measure the angle in one of many ways by the eyescrew you can use SOHCAHTOA to calculate the legs of the hypotenuse.
The adjacent boom leg would be FcosA and the cabinent leg would be FsinA.
Now you measure the actual weight of the hanging weight by simply hanging it from an appropriate spring scale and get the much harder reading of the boom force by attaching your spring scale to the eyescrew at the end of the boom and pulling it to the same cm reading you recorded above and have your partner read the spring scale.
The Big Picture:
1. Remember the etch-a-sketch when you drew a right triangel? The hypotenuse was made by turning a vertical knob and horizontal knob only. The exact amount of times you turned the horizontal knob equals the amount of times you turned it to draw the horizontal leg of your right triangle. The exact amount of times you turned the vertical knob to draw the hypotenuse equals the amount of times you turned it to draw the vertical leg of your right triangle. Thus the hypotenuse has the vertical and horizontal legs hidden in it allowing you replace the hypotenuse reading with the vertical and horizontal legs which have more meaning to us humans.
2. The force of the weight hanging down then equals the vertical leg (cabinent, FsinA) and the boom leg (FcosA) equals the force it took to pull against the string in the boom. Both of these are hidden in your hypotenuse reading.
3. Note that the legs are two vectors added tail to head (the boom direction into the boom and the cabinent leg up as it was holding the weight pulling down) and the scale reading hypotenuse is the resultant of these two vectors.
COOL HEY!