Equilibrium in 2D Video Lessons

Concept

# Problem: Your crazy uncle Mike has odd preferences for where weights should hang on the force table and an obssession with balance. He's only happy if a 130 g weight hangs from 0°, and a 190 g weight hangs from 137°.a) Draw a vector diagram (to scale) of the two given forces on the disc, labeling the weights and angles.b) Calculate the predicted weight and angle (ignore uncertainty) of the third force. Draw and label this third force to scale in the correct place on your vector diagram.c) The percent uncertainty = 1.71%; use this to calculate the mass uncertainty for the two given masses and propogate this uncertainty to find the uncertainty in the predicted magnitude for the third force (ignore angle uncertainty). Is this predicted third force consistent with the force from the third mass (with uncertainty) that you actually found in b?

###### FREE Expert Solution

a)

Even though mass is not a force, we do not need to convert the masses to forces when using a force table.

Using the forces in grams will help us in the third step when determining uncertainties.

A force of 130g acts at 0° while a force of 190 acts at 137°

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###### Problem Details

Your crazy uncle Mike has odd preferences for where weights should hang on the force table and an obssession with balance. He's only happy if a 130 g weight hangs from 0°, and a 190 g weight hangs from 137°.

a) Draw a vector diagram (to scale) of the two given forces on the disc, labeling the weights and angles.

b) Calculate the predicted weight and angle (ignore uncertainty) of the third force. Draw and label this third force to scale in the correct place on your vector diagram.

c) The percent uncertainty = 1.71%; use this to calculate the mass uncertainty for the two given masses and propogate this uncertainty to find the uncertainty in the predicted magnitude for the third force (ignore angle uncertainty). Is this predicted third force consistent with the force from the third mass (with uncertainty) that you actually found in b?