Forces Flashcards
Define force.
A force is either a push or pull that one object exerts on another.
Is a force a scalar or vecor quantity?
Vector. It is a magnitude acting in a certain direction.
Define contact force and give a few examples of them.
It is the force between objects that are in contact. Some of these forces include normal reaction force, friction and tension.
Defince non-contact force and give a few examples of them.
They are forces that do not require objects to be in contact. Some of these forces include gravitational force, electric force and magnetic force.
Name the effects of a force.
A force can:
Change the state of motion of an object.
Change the direction of a moving object.
Change the speed of a moving object (accelerate or decelerate).
Change the shape of an object.
What tools are used for measuring forces?
Compression spring balance and extension spring balance. These tools measure an object’s weight, and not the mass. The weight is about 10 (9.81) times its mass. This factor varies as it is the gravitational field strength of the environment.
Is tension a push or pull? In which direction does it act?
Tension is always a pull. It acts along the rope that is holding an object down, and acts in the opposite direction in which the object is pulling.
Define resultant force.
It is the overall net force acting on an object.
Define friction.
It is the force that opposes or tends to oppose motion between surfaces in contact.
What are the two conditions for the presence of frictional force?
Two surfaces must be in contact .
At least one surface must be uneven.
State Newton’s first law of motion.
Every object will continue in its state of rest or uniform motion in a straight line unless a resultant force acts on it.
State Newton’s second law of motion.
When a resultant force acts on an object of constant mass, it will accelerate in the direction of the resultant force.
State the formula of Newton’s second law.
F = ma
net F = resultant force (N)
m = mass of object (kg)
a = acceleration (m s^-2)
State Newton’s third law of motion.
If body A exerts a force F(AB) on body B, then body B will exert an equal and opposite force F(BA) on body A.
State the 4 characteristics of forces.
1.Forces always occur in pairs. Each pair is made of an action and a reaction.
2.Action and reaction forces are equal in magnitude.
3.Action and reaction forces act in opposite directions.
4.Action and reaction forces act on different bodies.
