Motion in 3-D

PHY430 – Lab 2

Pre-Lab Questions 2

Topic: Motion in One Dimension

Objective: 1. To enable the students to relate one dimensional motion of two masses

connected by a massless string to acceleration due to gravity.

2. Identify the independent, fixed and dependant variables in an equation used

in an experiment.

After answering these questions, the students will be able to

1. Use Newton’s 2nd law to derive

=

(

)

.

2. Determine the independent, fixed and dependent variables in this experiment.

3. Plan how to determine the acceleration of the masses by using a linear air tract,

and photo gate timer.

4. Identify the graph that will give g as its gradient.

PRE-LAB QUESTIONS 2

Answer the following questions and submit your group answer to the instructor.

1. Assume two masses (mA and mB) are connected by a string, as in Fig. 1, and mA is

sliding on a frictionless surface.

a

mA

mB

a

By applying Newton’s 2 nd Law to the system in Fig 1, derive the following

equation.

=(

)

…………(1)

1

PHY430 – Lab 2

a = acceleration of mA and mB

g = acceleration due to gravity

You may refer to Example 5.10 Acceleration of Two Objects Connected by a Cord

(Serway & Jewett, Physics for Scientists and Engineers with Modern Physics, 8th

Edition, p.121). Note: Referring to Fig. 5.15 (a) p.121, for the system in Fig. 1,  = 0o,

therefore sin  = 0.

2. If g is to be determined from equation 1, state the quantities that you need to

i)

vary (independent variable)

ii)

fix (fixed variable)

iii)

measure. (dependent variable).

3. The acceleration of mA in Fig. 1 can be determined by applying a kinematic

equation v2 = u2 + 2as. Describe how the acceleration can be determined if mA is

on a linear air-tract, passing through a photo gate timer, while a slotted mass

represents mB. You may refer Experiment 4 (Motion in One Dimesion) in the Old

Lab Manual for PHY430.

4. State the graph that you need to plot so that g can be determined from its gradient.

2

PHY430 – Lab 2

Experiment 2

Topic:...