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PEKA 5
PEKA 5
Relationship between mass and acceleration when force is constant.
Aim
To study the relationship between mass and acceleration of an object when the
force acting on the object is constant.
Problem
Statement
An object accelerates when it is acted upon by a force. What will happen to the
acceleration of the object if its mass increases but the force acting on it is still the
same?
Inference
The mass of an object influences its acceleration.
Hypothesis
When the force acting on an object is constant, the bigger is the mass of the
object, the smaller is its acceleration.
Variables
(a) Manipulated : Mass
(b) Responding : Acceleration
(c) Fixed : Force
Operational
Definition of
Variables
Acceleration : Rate of change of velocity that can be determined by analyzing the
ticker tapes.
Force : Constant force is achieved by pulling the elastic cord that is maintained at
a fixed length. A newton Balance is used to calibrate the force on th elastic cord
when it is pulled a total length of 10 cm.
Apparatus
Materials
Physics Unit, SMJK Yu Hua
Ticker timer, 12 V a.c. power supply, 1 trolleys and inclined plane. Triple Beam
Balance.
Slotted Weight, 50g, 100g, 150g. Thread, ticker tape and cellophane tape.
Pradeep Kumar
PEKA 5
Procedure
Ticker
Timer
Trolley
Ticker
Tape
Elastic
Cord
Friction compensated
inclined plane
12V ac Power
Supply
Lab Bench
Slotted
Weights
1. Arrange the apparatus as shown in the diagram. Compensate for friction.
2. Measure the mass of the trolley using the triple beam balance provided. Record
the value.
2. Switch on the ticker timer. Use a 50g slotted weight for a constant force.
3. Release the slotted weight to fall freely to the ground.
4. Analyse the ticker tape to determine the acceleration, a of the trolley and record
the value in the form of a table.
5. Repeat procedures 2 to 4 by using additional weights to put into the trolley’s
cointaiment. (Wooded Blocks)
6. Plot the graphs for
(a) acceleration against mass,
(b) acceleration against
.
Method
1. The apparatus were arranged as shown in the diagram.
2. Mass of the trolley was measured using a triple beam balance. The value of
mass was recorded.
3…… (Continue using passive voice.)
Physics Unit, SMJK Yu Hua
Pradeep Kumar
PEKA 5
Table of
Results
1. Cut the ticker tapes into stripes of 10 ticks and paste them here. Use at least 3
10 ticks tape to determine the acceleration. Calculate the acceleration for each
graph.
2. Draw a table and record the data.
a. 10 ticks Ticker tapes to calculate acceleration
b. Table of results
Mass of trolley / kg
/unit1
Acceleration, a/cm s2
X
Y
Z
Graphs
1. Plot the following graphs in the space provided below.
(a) Acceleration, a against mass, m.
(b) Acceleration, a against 1/mass, m1.
Discussion
1. From the plotted graph of acceleration against mass, state the relationship
between acceleration and the mass of the trolley when pulled by a constant force.
Does the result support your hypothesis?
The graph shows that the bigger the mass of the object, the smaller is the
acceleration when the force acting on the object is constant. The hypothesis is
supported.
2. From the plotted graph of acceleration against 1/mass, write one mathematical
relationship between acceleration and mass if the applied force is constant.
Acceleration, a is inversely proportional to mass, m when the applied force, F is
constant, a  1/m, F constant.
Physics Unit, SMJK Yu Hua
Pradeep Kumar
PEKA 5
Conclusion
Acceleration of the trolley is inversely proportional to its mass when the force is
constant.
Precaution
Do not tilt the runway with a very large angle of inclination. Pratice
compensating for friction of the runway until the right angle is achieved.
Make sure the trolley sits properly on the runway and is easily moved.
Physics Unit, SMJK Yu Hua
Pradeep Kumar