Download Newton`s Second Law

Theme 1: On the Move
Investigating Newton's second law of motion
Aim: To investigate how the acceleration of a trolley
depends on the force keeping the mass constant.
OBJECTIVE: To consider various forces and how they affect the
motion of objects, particularly the motion of a trolley moving along a
frictionless air track.
Focus Questions

Do forces cause motion or change in motion (acceleration)?

What is meant by acceleration? What are its units?

Is acceleration a scalar or a vector? Does it have size and
direction?

Do you think that a falling object velocity will increase with
time or will it remain constant?

What does Newton’s second law states?

Do you think that the force produced by the falling object is
proportional to the acceleration of the trolley?

What factor must we keep constant for this experiment to
work?
Safety
Take care when masses fall to the floor. Use a box or tray to collect the
fallen masses. This will prevent loss of small masses. Choose a length of
string such that the mass does not touch the ground until the trolley
nearly reaches the pulley.
Ninu Cremona Lyceum – Gozo College – Physics Department
Page 1
Date: ____________
Theme 1: On the Move
Aim : To investigate how the acceleration of a trolley
depends on the force keeping the mass constant.
Apparatus : Light gates, electronic timer , trolley and air
track, Pulley and string , Various masses, 5 g each,Clamp
,Ruler ,string.
Sources of error and precautions 

Method
1. The air track is set up and adjusted on a horizontal surface. A
string is attached to the trolley at one end passed through a pulley
and attached to a bucket at other end.The distance of the light
gate from each other was set to 50 cm.
2. A weight of 5 gram is attached to the trolley to act as a force. The
counter is switched on and the trolley is placed just before the first
light gate. The trolley is released and the force in the bucket
pulled the trolley along the air track and the time taken are
recorded.
3. This procedure is repeated each time adding one mass of 5 grams.
The time obtained is recorded in the result table. The whole
method is repeated for each different force until a set of 6
readings are obtained.
Ninu Cremona Lyceum – Gozo College – Physics Department
Page 2
Results:
Mass
g
0
5
10
15
20
25
30
Mass
Kg
Distance
S
M
Time
t
s
Time
t2
s
Acceleration
a= 2S
t2
Force
N
W=mg
0.50
0.50
0.50
0.50
0.50
0.50
0.50
A graph is drawn of acceleration (y axis ) against Force (x axis).
Discussion /Evaluation:
1. From the results what happens to the time and
acceleration as the force is increased? Why?
2. What happens to the acceleration when the force is
doubled?
3. Describe the line you obtained from your graph. What
does this line represents? What is the relationship
between force and acceleration?
4. Did your graph pass from the origin? If not why?
5. Do the results obtained agree with Newton’s 2nd law of
motion?
6. Does the theoretical value match your measurement
within error? If not, comment on possible sources of error
in the measurement.
Ninu Cremona Lyceum – Gozo College – Physics Department
Page 3