SP9- Forces And Their Effects Flashcards
What are contact forces
When objects interact by exerting forces on each other and the objects are touching
What’s the normal contact force
When you stand on the floor, there is an upwards force from the floor on you
What is resistance a form of
A form of friction - slows down an object
Water resistance is a contact force
How is upthrust balanced
It’s a contact force and is balanced by the non contact force called gravity, it doesn’t need to touch the boat to give it weight
Where can gravity occur
Between any two objects that have mass
How can the gravitational forces between the two objects with mass be represented
As vectors (arrows that show both direction and magnitude ) these two forces are action reaction forces
What are action reaction forces
Pairs of forces acting on different objects in opposite directions
What’s a force field
The space around an object where it can affect other objects - the moon and earth affect each other becuase the moon is within the earths gravitional field and vice versa
What types of force are magnetism and static electricity,
Non contact
Tell me about magnetism
a magnet can attract objects made from magnetic materials including iron, nickel and cobalt
There is a space around a magnet where it can affect other materials called the magnetic field
Tell me about an electric field (electrostatic field)
An object charged with static electricity has an electric field - two objects with the same charge that are close to each other produce a pair of forces that are equal in size and acting in opposite directions
What is the resultant force (net force)
The overall force - if it’s 0 the forces are said to be balanced
When a plane is flying at a constant velocity and height, the horizontal and vertical forces on it are balanced, resultant force is 0
How can we show forces on a object
Using a free body force diagram
- shows Arrows with force
Length of arrows represents the size of the force
How can we find the resultant force using a scale diagram
Draw arrows at correct angles to represent the forces, length should represent size
Draw lines to make a parallelogram
Resultant force is the diagonal of the parallelogram, measure the arrow to work out the size of the force
How can we work out how much thrust is pushing the plane up and how much is pushing it forwards
By resolving the thrust force into 2 component forces, forces at right angles to each other - can be done using a scale diagram, draw force arrows to scale, make a rectangle with sides in the directions your interested in - the resolved forces are the sides of the rectangle
