Forces Flashcards
Define force
A force is a push or pull that can cause an object to change its motion, speed up, slow down, or remain stationary.
Define dynamics
Dynamics is the study of the causes of motion (forces).
Define system diagram
A system diagram is a simple sketch of all the objects involved in a situation.
Define free body diagram
A free body diagram is a simple drawing of an object showing all the forces acting on it.
Define applied force (Fapp)
A force that results when one object makes contact with another and pushes or pulls it.
Define tension (Ft)
A pulling force from a rope or string.
Define friction (Ff)
A motion which opposes the sliding of two surfaces across one another; friction acts opposite motion or attempted motion.
Define normal force (Fn)
A perpendicular force exerted by a surface on an object in contact with the surface.
Define force of gravity
A force of attraction between any 2 objects due to mass.
What are non-contact forces also called?
Action at a distance forces
What is Newton’s first law?
Newton’s first law states that if the net external force on an object is zero, the object will remain at rest or continue to move at a constant velocity.
Define inertia
Inertia is the property of matter that causes an object to resist changes in motion.
How are inertia and mass related?
Inertia is directly proportional to the mass of an object.
What is Newton’s second law?
Newton’s second law states that if the net external force on an object is not zero, the object will accelerate in the direction of this net force.
How are acceleration and the net force related?
The object’s acceleration is directly proportional to the an object’s net force.
How is an object’s acceleration and mass related?
The object’s acceleration is inversely proportional to an object’s mass.
What is Newton’s third law?
Newton’s third law states that for every force, there is a simultaneous reaction force that is equal in magnitude but opposite in direction.
What are the action/reaction force properties?
The action/reaction forces happen at the same time but act on different objects.
When an object is tied together by a rope/string, it is experience the same __________.
Acceleration
What direction does air resistance act in?
Air resistance acts in the opposite direction of the velocity of an object.
Define terminal speed
Terminal speed is the maximum constant speed of a falling object.
Define mass
Mass is the quantity of matter in an object.
Define weight
Weight is a measure of the force of gravity acting on an object.
How can you change mass?
The only way to change mass is to add or remove matter.
How can you lose weight?
The only way you can lose weight is the escape Earth’s gravitational field of 9.8 m/s squared that is acting on an object on Earth at all times.
Define static friction (Fs)
Static friction is a force that prevents a stationary object from starting to move.
Define kinetic friction (Fk)
Kinetic friction is a force that opposes the motion of a moving object. It is caused by the surfaces in contact with one another.
What is harder to move: static friction or kinetic friction?
Static friction is harder to move because the applied force must over the static friction’s max threshold in order for the object to start moving.
What are the 2 factors that affect friction?
The types of surfaces and the normal force acting on an object.
Define coefficient of friction
The coefficient of friction is the ratio of the force of friction acting on an object to the normal force.
What happens when a car hydroplanes?
When a car hydroplanes, it means it is not touching the surface therefore it has no friction acting on it. A standard car has treads 7-8 mm deep to allow water/snow to squeeze through the tire and maintain the tire’s contact with the road. If the treads start to wear out less water gets in thus allowing for the tire to start moving on water. This is dangerous because there is no friction acting on the car.
What are some characteristics of an artificial hip?
An artificial hip must be able to function properly because it needs to support the whole upper body. For this, the materials need to be flexible yet sturdy, resistant and durable. It must be able to work for a long time and resist wearing down.
