Chapter 8: Forces In Balance Flashcards
What is displacement?
It is distance without change in direction, displacement is distance in a certain direction
What is a vector?
A vector is a physical quantity which has magnitude and direction
e.g. acceleration, force, momentum, weight
What is a scalar?
A scalar quantity has magnitude but no direction
e.g. speed, distance, time , mass
How can a vector quantity be represented?
It can be represented by an arrow in the direction of the scalar
The length in proportion to the magnitude of the vector
In what ways can force change an object?
Forces can change the shape of an object or change its motion or state of rest.
What is a contact force?
A contact force is a force that acts on objects only when the objects touch eachother
What always happens when two objects interact?
They always exert equal and opposite force on each other
What is the centre of mass of an object?
It is the point where its mass can be thought of as being concentrated
What happens when an object is freely suspended?
It comes to rest with its centre of mass directly underneath the point of suspension
What will always be the center of mass of a symmetrical object?
Is along the axis of symmetry
Describe how to find the centre of mass of an object.
Put a hole in the corner of the object
Suspend it from the rod
Use a plumb line to draw a line on the object from the rod
Repeat the process hanging the card from a different corner each time.
The points where the lines meet is the centre of mass
What is the resultant force?
It is a single force that has the same effect as all the forces acting on an object
Is the resultant force of an object is 0 what happens to the object?
The object stays at rest or at the same speed or direction
Is the resultant force of an object is greater than 0 what happens to the object?
The speed or direction of the object will change
If two forces act on an object along the same line the result force is either?
Their sum, if the forces act in the same direction
Ot their difference if the forces act in opposite directions
