forces Flashcards
What is a scalar quantity?
A scalar quantity has magnitude only.
What is a vector quantity?
A vector quantity has magnitude and an associated direction.
How can a vector quantity be represented?
A vector quantity may be represented by an arrow, where the length represents magnitude and the direction indicates direction.
What is a force?
A force is a push or pull that acts on an object due to interaction with another object.
What are the two types of forces?
- Contact forces
- Non-contact forces
What are examples of contact forces?
- Friction
- Air resistance
- Tension
- Reaction
What are examples of non-contact forces?
- Gravitational force
- Electrostatic force
- Magnetic force
Is force a scalar or vector quantity?
Force is a vector quantity.
What is weight?
Weight is the force acting on an object due to gravity.
What does the weight of an object depend on?
The weight of an object depends on the gravitational field strength at the point where the object is.
Where does the weight of an object act?
The weight of an object acts at a single point referred to as the object’s ‘centre of mass’.
How are weight and mass related?
Weight and mass are directly proportional.
How is weight measured?
using a newton meter (and to measure other forces)
What is a resultant force?
A resultant force is a single force that has the same effect as all the original forces acting together.
What should you be able to calculate regarding forces?
resultant of two forces that act in a straight line.
What is the significance of free body diagrams?
Free body diagrams help describe qualitatively examples where several forces lead to a resultant force on an object.
What can a single force be resolved into?
A single force can be resolved into two components acting at right angles to each other.
How much work is done when a force of one newton causes a displacement of one metre?
One joule of work is done.
What happens to work done against frictional forces?
Work done against frictional forces causes a rise in the temperature of the object.
What must be applied to change the shape of an object?
More than one force has to be applied to change the shape of an object (limited to stationary objects).
What is the difference between elastic deformation and inelastic deformation?
Elastic deformation returns to original shape, while inelastic deformation does not.
What does Hooke’s Law state?
The extension of an elastic object is directly proportional to the force applied, provided that the limit of proportionality is not exceeded.
What is elastic potential energy in a spring?
Elastic potential energy is stored in the spring when it is stretched or compressed.
What is the relationship between work done on a spring and elastic potential energy?
The work done on the spring and the elastic potential energy stored are equal, provided the spring is not inelastically deformed.
