lab quiz #7

#1 F=m*g then K=F/x
don't forgett to convert to SI answer neg
#2 T= 2pi*sqrt(mass of glider/K)
answer neg

I ask for input on #3 constant = 2*pi so
T=2*pi*k^-.5 with expression 8: 2*pi*k^-.5*(deltaT/T)?
any thoughts?

I don't have Quiz 7 there yet ??

quiz is up now,

what is K ?

Well for number four you must first calculate the period.
After you have done this, you propogate the error of the spring with equation 8 from error and uncertainty.
Then, to get the absolute error of the period, you multiply the new error by the period. PRESTO!

For number 3 they give you the relative error of K (the percentage is equal to Delta_K/K). To propagate it, follow equation 8 from errors and uncertainty.... so just multiply by abs(-1/2) to get the relative error of T. Then multiply by T.

Full Equation: 2*pi*sqrt(m/k) * 0.5* (% given/100)

You suspend a 18.7 gram mass, which is attached to a spring via a string guided by a pulley as shown above. You define this position of the glider shown as your "zero mass" starting position (the glider plays no role here other than providing a convenient object to attach the string to and measure position with). When you add 37.4 grams to the initial mass you produce a shift of the glider of 21.3 cm. This is also the stretch from the starting position produced in the spring. What is the spring constant of the spring (see Ch9 sheet 14)? Indicate with negative (positive) sign whether a compression of the spring by the same force as above would compress the spring by the same distance as (a distance different from) the stretch above.

I can't seem to figure it out. I converted all to SI units. The eqn used should be F=Kx and F=mg. Find the force by multiplying mass (i tried both ways, just the .374 and adding it to the original grams) multiply it by gravity. Then that resulting force divided by the displacement. I can't figure out the k. I have tried both neg and positives, although I feel that the answer is negative. Any help??

Q2. You displaced the glider shown above from its equilibrium position by 20.3 cm and then released it. In the following oscillation of the glider the computer, with the help of a photogate, measures the time between two subsequent passes of the glider through the gate, i.e. the period T of the oscillation. If the spring constant of the two springs combined is 3.23 N/m, and the mass of the glider is 376 grams, what is the expected period (to be compared with the measured period)(see Ch9 sheet 16)? Indicate with a negative (positive) sign whether the spring constant of the two identical springs combined is twice the (has the same) spring constant as a single spring.

Q3. In the experiment with the two springs shown above you calculate the expected period , where k= 2.69 N/m is the spring constant of the two springs combined, and m= 380 grams is the mass of the glider. You neglect the error of m. What is the absolute errror of the expected period T, when the error of the spring constant for one spring is 6.03 %? Indicate with a positive (negative) sign whether the % error of the spring constant of two identical springs combined is equal to (twice) the % error of the spring constant of a single spring. (Hint: since the mass is treated as error free, the period can be written for the purpose of error calculation in the form "T=const x k-1/2". Use expression ( and (3) in "Error and Uncertainty".)

any ideas???

Could someone please post question three with all the numbers because I have tried to do it atleast 15 different ways and I keep getting it wrong. Please help on question 3?????

I am also stuck on question three I have tried it so many different ways but I cant figure it out can someone please post a detailed solution for this problem?

for #1

what is the value of x?

K=F/x

x would be the distance given.

any help with #1?

Please help with #3 I cant figure it and I have tried everything I can think of?

help me with 1, i'll hlep with 3

You suspend a 18.7 gram mass, which is attached to a spring via a string guided by a pulley as shown above. You define this position of the glider shown as your "zero mass" starting position (the glider plays no role here other than providing a convenient object to attach the string to and measure position with). When you add 37.4 grams to the initial mass you produce a shift of the glider of 21.3 cm. This is also the stretch from the starting position produced in the spring. What is the spring constant of the spring (see Ch9 sheet 14)? Indicate with negative (positive) sign whether a compression of the spring by the same force as above would compress the spring by the same distance as (a distance different from) the stretch above.

F=m*g then K=F/x
answer is negative

Convert 37.4 grams to Kilograms .0374
F= .0374/9.81
F=.0038124363

K=F/x
K= .0038124363/x
21.3 cm converted to meters .213
K=.0038124363/.213
K=-.0178987619

Thats question 1 could you please post question 3?