2.06 Forces in balance Flashcards
What is a force?
A force is a push or a pull, exerted by one object on another. It has direction as well as magnitude (size), so it is a vector.
What is the SI unit of force?
The SI unit of force is the newton (N).
How can small forces be measured?
Small forces can be measured using a spring balance. The greater the force, the more the spring is stretched and the higher the reading is on the scale.
What is upthrust?
The upward force from a liquid or gas that makes things float.
What is weight?
The gravitational force on an object.
What is tension?
The force in a stretched material.
What is friction?
The force that opposes the motion of one material sliding past another.
What is thrust?
The forward force of an aircraft engine.
What is air resistance?
One type of friction.
Why do objects come to rest on Earth?
On Earth, unpowered objects come to rest because of friction.
What will happen if there is no force acting on a moving object?
With no friction, gravity, or external force acting on it, a moving object will keep on moving for ever at a steady speed, in a straight line.
Newton’s first law of motion
An object at rest remains at rest, or if in motion, remains in motion at a constant velocity unless acted on by a net external force
What are the two possible options when a balanced force is acting on an object?
With balanced forces on it, the object is either at rest or moving at a steady velocity.
What is terminal velocity?
Terminal velocity is when the resultant force is 0. Since the net force is 0, there is no change in velocity so the object keeps moving at a constant velocity.
Terminal velocity is the maximum speed attainable by an object as it falls through a fluid.
