Lab 3- Centre OF MASS AND Rotational Inertia Worksheet V3 PDF

Preview

Summary

Lab 3 worksheet...

Description

Lab 3-CENTRE OF MASS & ROTATIONAL INERTIA WORKSHEET/10 LAST NAME:

FIRST NAME:

STUDENT ID:

TABLE #:

TIME:

DAY:

Experiment 1 Determine the distance D from the centre of gravity (xcm, ycm) to the point X



Use the five distance measurements from your row to calculate the mean and its uncertainty D(

±

D=

cm )

cm 

Experiment 2 Determine the unknown mass ⟨ M 1 ⟩ ± ∆ M 1

Sketch a pseudo real diagram of your apparatus below indicating the known mass M and its position d 1; the unknown mass M1 and its position d2; the direction and magnitude of the weight forces; and the direction and magnitude of both torques about the pivot point.

Use the five mass measurements from your row to calculate the mean and its uncertainty M (kg)

d1 (m)

Torque 1 (Nm)

d2 (m)

⟨ M1 ⟩

M1 (



=

kg )

kg

⓪①②





Experiment 3 Determine the mass of balance arm ⟨ M 2 ⟩ ± ∆ M2

Sketch a pseudo real diagram of your apparatus below indicating the known mass M and its position d 1; the rulers mass M2 and its position d2; the direction and magnitude of the weight forces; and the direction and magnitude of both torques about the pivot point.

Use the five mass measurements from your row to calculate the mean and its uncertainty. M (kg)

d1 (m)

Torque 1 (Nm)

Page 1 of 3

d2 (m)

⟨ M2 ⟩

M2 (



=

kg )

kg 

⓪①②

Experiment 4 Determine the moment of inertia pre-factors for rotation of the balance arm

Use discretization to evaluate the rotational inertia of a 1 m ruler and determine the reciprocal of the 1/n prefactor. Mass of 10 cm bit, mi (kg) i

About end of ruler ri (m) ri2 (m2)

1

0.05

2

0.15

3

0.25

4

0.35

5

0.45

6

0.55

7

0.65

8

0.75

9

0.85

10

0.95 .

I1

∑r

2 i

.

i

= mi ∑ r i

2

I2

i

2

∑ r2i i 2 = mi ∑ r i i

2

n1=M L /I 1 (3 sig. fig.)

n2=M L /I 2

n1 (integer) 

About centre of ruler ri2 ri (m)

n2 (integer)

Experiment 5 Investigate the effect of rotational inertia on rolling motion

You are going to perform a rolling race with the four objects listed in the table below. Predict the order that each object crosses the finish line. For the large disk complete the pseudo real force diagram and write an expression for the angular acceleration. Record the race and sketch the angular position and angular velocity behaviour vs time for each object. Object

I Equation

Prediction

Observation

Small disk Fat disk Large disk Small ring

Page 2 of 3

Page 3 of 3...