Lab Report Format Expectations
Utilize college level grammar and formaṄng when answering text based questions.
Report all equations in a proper mathematical format, with the correct signs and symbols.
Submissions with incomplete or improperly formatted responses may be rejected.
Pre-Lab Questions
• This lab contains two different experiments that cover two different aspects of friction. In your
own words, describe both concepts and how each experiment demonstrates them.
The two aspects of friction are static Friction and kinetic friction. Static Friction is the force that is
put on an object to return to rest after it has been moved from an initial position. Certain objects
can be heavy enough in mass to where the friction of the object keeps it in place, lifting or
pushing by hand is not enough to move the object because the friction is greater than the force
that is pushing against it. Kinetic Friction is when an object is moved and has to work through
friction as the object is moving across different surface layers. An incline plance can change the
static friction of an object because the higher the incline the more likely static friction cannot
keep the object from sliding off. The mass of the object can also determine how much incline the
object can manage. Otherwise; Kinetic Friction will occur and slide against the incline due to
Kinetic Friction
• The normal force plays an important role when studying friction. Describe the relationship
between friction and the normal force.
The normal force is exerted to the surface perpendicular and is always in contact with the object.
When an object is placed on a flat surface, the normal force is always the same and never
changes. The direction of the object changes due to gravity and the surface layer that supports
it. In relation to friction, friction can only occur if the object is in contact with another object
because friction is a force that applies pressure when there is motion between the two objects.
When enough force is placed between both objects, then friction causes the object to move.
EXPERIMENT 1: STATIC FRICTION AND MASS ON AN INCLINE PLANE
Introduction Questions
• Explain, generally, what you will do for Experiment 1.
I will be using an incline plane and place different objects on top of it to observe the normal
force, and calculate the coefficient of static friction, and kinetic friction.
, • If the normal force only acts perpendicular to a surface, what happens to the magnitude of the
normal force on an object as the angle of the incline is increased?
The magnitude of the normal force decreases.
• Applying Newton’s Second Law and the equation for static friction (F = μsN), we can prove that
the coefficient of static friction (μs) is related to the minimum angle, θ, that causes the block to
slip (see Figure 5) by the equation μs = tan(θ). Starting with the knowledge that the total force on
an object is the force acting in one direction, minus the force of friction which opposes it:
Fnet = Facceleration - Ffriction
solve for this relationship - μs = tan(θ). Hint: Break this down into the x and y components of
sin(θ) .
force and remember the trigonometric identity tan (θ)=
cos(θ)
Fnet=mgsin(theta), Fs=MsN=Ms*mg*cos(theta), Fnet=fsmg*sin(theta)=ms*mg*cos(theta) or
ms=(mg*sin(theta))//(mg*cos(theta)), (Final Part) Ms=tan(theta).
Figure 5: A block slipping down a ramp.
• Suppose you know the coefficient of static friction, and you want to solve for the minimum angle
from the equation μs = tan(θ). How can you solve for θ, here?
Step1 u=tan(θ), Step2 arctan(u)=arctan(tan(θ)), Step 3 (Simplify) θ=arctan(u).
Utilize college level grammar and formaṄng when answering text based questions.
Report all equations in a proper mathematical format, with the correct signs and symbols.
Submissions with incomplete or improperly formatted responses may be rejected.
Pre-Lab Questions
• This lab contains two different experiments that cover two different aspects of friction. In your
own words, describe both concepts and how each experiment demonstrates them.
The two aspects of friction are static Friction and kinetic friction. Static Friction is the force that is
put on an object to return to rest after it has been moved from an initial position. Certain objects
can be heavy enough in mass to where the friction of the object keeps it in place, lifting or
pushing by hand is not enough to move the object because the friction is greater than the force
that is pushing against it. Kinetic Friction is when an object is moved and has to work through
friction as the object is moving across different surface layers. An incline plance can change the
static friction of an object because the higher the incline the more likely static friction cannot
keep the object from sliding off. The mass of the object can also determine how much incline the
object can manage. Otherwise; Kinetic Friction will occur and slide against the incline due to
Kinetic Friction
• The normal force plays an important role when studying friction. Describe the relationship
between friction and the normal force.
The normal force is exerted to the surface perpendicular and is always in contact with the object.
When an object is placed on a flat surface, the normal force is always the same and never
changes. The direction of the object changes due to gravity and the surface layer that supports
it. In relation to friction, friction can only occur if the object is in contact with another object
because friction is a force that applies pressure when there is motion between the two objects.
When enough force is placed between both objects, then friction causes the object to move.
EXPERIMENT 1: STATIC FRICTION AND MASS ON AN INCLINE PLANE
Introduction Questions
• Explain, generally, what you will do for Experiment 1.
I will be using an incline plane and place different objects on top of it to observe the normal
force, and calculate the coefficient of static friction, and kinetic friction.
, • If the normal force only acts perpendicular to a surface, what happens to the magnitude of the
normal force on an object as the angle of the incline is increased?
The magnitude of the normal force decreases.
• Applying Newton’s Second Law and the equation for static friction (F = μsN), we can prove that
the coefficient of static friction (μs) is related to the minimum angle, θ, that causes the block to
slip (see Figure 5) by the equation μs = tan(θ). Starting with the knowledge that the total force on
an object is the force acting in one direction, minus the force of friction which opposes it:
Fnet = Facceleration - Ffriction
solve for this relationship - μs = tan(θ). Hint: Break this down into the x and y components of
sin(θ) .
force and remember the trigonometric identity tan (θ)=
cos(θ)
Fnet=mgsin(theta), Fs=MsN=Ms*mg*cos(theta), Fnet=fsmg*sin(theta)=ms*mg*cos(theta) or
ms=(mg*sin(theta))//(mg*cos(theta)), (Final Part) Ms=tan(theta).
Figure 5: A block slipping down a ramp.
• Suppose you know the coefficient of static friction, and you want to solve for the minimum angle
from the equation μs = tan(θ). How can you solve for θ, here?
Step1 u=tan(θ), Step2 arctan(u)=arctan(tan(θ)), Step 3 (Simplify) θ=arctan(u).
