Study of Circular Motion
Purpose of Study
In our everyday life, we experience the circular motion in several ways in
different contexts. Examples are making a sharp turn in a car on a corner,
enjoying the ride on a roller coaster, swirling a football by kicking the ball
and scoring a goal, etc. The forces associated with the circular motion, like
the centripetal and centrifugal forces, play an integral role in designing dif-
ferent objects and structures. An example of that is the optimized design
of the rear wing of a race car. This optimized design results in increased
downforce exerted by the wind that increases the frictional force between the
ground and the race car wheels and prevents the race car from flinging out
from the racetrack.
Here we are devising an experiment to determine the mass, a crucial param-
eter in the engineering designs, of a metal roller resting on a turntable. The
required tools are:
1. A turntable.
2. A clock to measure time
3. An inelastic string
4. A scale to read the magnitude of the tension in the string.
5. A linear scale to determine the distance of the metal roller from the
centre.
Procedure
The turntable is set to rotate at a particular speed. As the turntable
rotates, a tension is developed in the string that works as the centripetal
1
, force and prevents the metal roller from moving outwards. The thread is
attached to a scale that measures and displays the tension generated in the
string. The distance of the metal roller is varied from the centre and the
reading of the scale is noted. After collecting a set of data, each individual
value of the data set is compared with the concerned governing equation of
the centripetal force and mass of the rotating body.
The underlying model or equation that can be used to compare the ex-
periment results with the theoretical one is:
2
~ 4π m
F = r
T2
Where:
1. F~ = Tension in the string, the centripetal force.
2. m= Mass of the metal cylinder.
3. T = Time-period of the turn table.
2
Purpose of Study
In our everyday life, we experience the circular motion in several ways in
different contexts. Examples are making a sharp turn in a car on a corner,
enjoying the ride on a roller coaster, swirling a football by kicking the ball
and scoring a goal, etc. The forces associated with the circular motion, like
the centripetal and centrifugal forces, play an integral role in designing dif-
ferent objects and structures. An example of that is the optimized design
of the rear wing of a race car. This optimized design results in increased
downforce exerted by the wind that increases the frictional force between the
ground and the race car wheels and prevents the race car from flinging out
from the racetrack.
Here we are devising an experiment to determine the mass, a crucial param-
eter in the engineering designs, of a metal roller resting on a turntable. The
required tools are:
1. A turntable.
2. A clock to measure time
3. An inelastic string
4. A scale to read the magnitude of the tension in the string.
5. A linear scale to determine the distance of the metal roller from the
centre.
Procedure
The turntable is set to rotate at a particular speed. As the turntable
rotates, a tension is developed in the string that works as the centripetal
1
, force and prevents the metal roller from moving outwards. The thread is
attached to a scale that measures and displays the tension generated in the
string. The distance of the metal roller is varied from the centre and the
reading of the scale is noted. After collecting a set of data, each individual
value of the data set is compared with the concerned governing equation of
the centripetal force and mass of the rotating body.
The underlying model or equation that can be used to compare the ex-
periment results with the theoretical one is:
2
~ 4π m
F = r
T2
Where:
1. F~ = Tension in the string, the centripetal force.
2. m= Mass of the metal cylinder.
3. T = Time-period of the turn table.
2
