Dynamics of particles lab

FACULTY OF ENGINEERING AND TECHNOLOGY
DEPARTMENT OF MECHANICAL ENGINEERING
Course: MMB 241 – Dynamics of Particles
Title of the Experiment
Date of the Experiment
04/04/2019
Student Name
Gotlhe Mothibedi
Student ID
201701335
INCLINED PLANE (L-2)
1.
Aims/Objective of the experiment (3)
The aim of this experiment is to investigate the forces parallel and normal on an inclined plane.
2.
Material/Apparatus Used – describe the apparatus and provide picture (5)
Work panel- an upstanding support for all the other apparatus
Inclined plane- a flat supporting surface tilted at an angle
Roller- acts as the load
Pulley arm- supports one of the pulleys
Weight hangers- used to provide support for the weights
Weights- used to apply forces on the roller
3.
Background information – explain the operation and theory of an inclined plane and its application. Provide a freebody-diagram of the forces acting on the object on the incline plane (6)
4.
Experimental Procedure (10)
Explain Procedure followed in the experiment
Any surfaces (rubber, wood, plastic) were removed from the inclined plane. The roller mass was found first using the
end pulley on the incline plane and a weight hanger. This was carried out by putting in the 10g masses in the weight
hanger until it almost balances with roller and then putting in the 1g masses for a more accurate adjustment. The mass
was the recorded and converted to weight, W. The apparatus was then set up as in Fig. 1 with the inclined plane set at an
initial angle of 15°. Using the roller weight W, WsinƟ and WcosƟ were calculated to predict the parallel and normal
reaction forces for angle Ɵ. The roller was placed at the bottom of the plane with one of its cords over the pulley fixed at
the end of the plane and the other cord over the pulley above the plane. The empty weight hangers were connected to the
ends of the cords. Weights were then slowly added to the weight hangers until the roller just lifted off and the normal
reaction cord was perpendicular to the plane which was achieved using the 1g weights for fine adjustment. The actual
normal and parallel forces were then recorded and converted to forces. The procedure was then repeated for 25°, 35°,
45° and 55° angles.
5. Results (12)
a.
Table of Results
Table 1 Inclined plane against forces (Rn and Rp)
Mass of Roller(g): 200
Force W (N): 1.962
Plane
angles(θ)
[degrees]
15
25
35
45
55
Actual
Normal
Reaction
(Mass)
[g]
Actual
Normal
Reaction
Force(Rn)
[N]
190
180
160
140
110
1.8639
1.7658
1.5696
1.3734
1.0791
Predicted
Parallel
Reaction
Force
Rp = Wsinθ)
[N]
0.5078
0.8292
1.1254
1.3873
1.6072
Actual
Parallel
Reaction
Mass
[g]
Actual
Parallel
Reaction
Force (Rp)
[N]
52
90
130
150
170
0.5101
0.8829
1.2753
1.4715
1.6677
Plot the results on a chart of Normal and Parallel Forces (both predicted and actual) vs Angle of Inclination
ACTUAL AND PREDICTED NORMAL FORCES VS ANGLE
OF INCLINATION
2
1.8
1.6
1.4
FORCE (N)
b.
Predicted
Normal
Reaction
Force
Rn = WCosθ
[N]
1.8951
1.7781
1.6072
1.3873
1.1254
1.2
1
0.8
0.6
0.4
0.2
0
0
10
20
30
40
ANGLE OF INCLINATION, Ɵ (°)
Series1
Series2
50
60
ACTUAL AND PREDICTED PARALLEL FORCES VS ANGLE OF
INCLINATION
1.8
1.6
FORCE (N)
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0
10
20
30
40
ANGLE OF INCLINATION, Ɵ (°)
Series1
Series2
Series3
50
60
6.
a.
Discussion and Conclusion (10)
Comment on all the forces acting on the object on the incline plane. What about the frictional force? (4)
Mg is the force due to gravity which is subjected on the load vertically downwards. MgcosƟ and mgsinƟ are the x and y
components of the weight (mg) of the load. N is the normal force acting as a reaction force on the load from the surface
and is perpendicular to the plane surface. T is the tension force subjected on the load by the cables/cords. F is the
frictional force acting opposite the motion of the load.
b.
Comment on the shape of graph plotted and explain any sources of errors. (3)
As the angle of inclination increases the normal forces decrease while the parallel forces increase such that they cross
each other at a point and hence form a cross shape. Due to the slight misshape of the actual forces with reference to the
predicted forces there is an indication of the presence of errors during the experiment. Parallax error could be one source
of error encountered when setting incline plane to a certain angle, Ɵ. Another possible source of error could be
unremoved stiction in the pulleys which obviously affects the results negatively.
c.
Indicate problem encountered during the experiment. (3)
A few times the pulleys got stuck a little bit due to the presence of stiction in the pulleys.
7.
Reference – provide references using APA citation system (4)
References:
Any appropriate reference material, written in the correct APA format.
…