# EXPERIMENT 5

```THE COPPERBELT UNIVERSITY
School of Mathematics and Natural Sciences
DEPARTMENT OF PHYSICAL SCIENCE
NAME: CHILUFYA MUMA
SIN: 13057650
PROGRAMME: BACHELOR OF SCIENCE (NON-QUOTA)
COURSE: PHYSICS
COURSE CODE: PH 110
GROUP: B 2-7
LECTURER: MR SIMFUKWE
DUE DATE: 13 AUGUST, 2013
INSTRUCTOR: MR FUNDAMWANGO
EXPERIMENT: 5
PARTNERS: PATRICIA
BASIL CHANGA
AKIM
NDINAWE NALOMBA
MATEYO
MAXWELL
BARNABAS
EXPERIMENT 5: COEFFICIENTS OF FRICTION
AIM: To determine the coefficient of static and kinetic friction between two
wooden blocks.
APPARATUS: A horizontal plane, a frictionless pulley fixed at one end, a wooden
block with a hook, weight box, scale pan and string.
THEORY:
The force of resistance encountered when one tries to slide one surface over the
other is known as friction. This force of resistance is tangential to the surface in
contact. Friction is directly proportional to the normal force. The constant of
proportionality is called the coefficient of friction. Frictional force is equal to;
f = µsFN
(1)
In the above equation, µs is the coefficient of friction and FN is the normal force.
When the surfaces in contact are sliding over each other and are in motion, the
force of friction is;
f = µKFN
(2)
In the above equation, µK is the coefficient of kinetic friction.
FN
Wooden
Block
W
Scale pan
Figure 1 Horizontal plane
PART 1: Static Friction
PROCEDURE:
1. The scale and wooden block were weighed separately.
2. The scale pan and wooded block were tied with the sting that was given.
3. The wooden block was placed on the horizontal block and the point was
marked with chalk and the string was allowed to pass over the frictionless
pulley so that the scale pan was on the over side below the pulley.
4. Weights were added on the scale pan till the wooden block begun to slide
and the weights were noted.
5. The experiment was repeated by adding weights of 50g, 100g, 150g, 200g
on top of the wooden block, each time starting from the same marked
point on the plane.
PART 2: Kinetic Friction
PROCEDURE:
1. A weight was place on the scale pan and it was given a slight push towards
the pulley.
2. Weights were increased on the scale pan and the block was given a slight
push until it was found to continue moving with a steady small velocity.
3. The corresponding weights on the scale pan were recorded.
4. The experiment was repeated by adding weights on 50g, 100g, 150g, 200g
on top of the wooden block, starting always from the small position on the
wooded plane.
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