4.6.1 Forces and Energy Flashcards
What is the difference between a contact and non-contact force?
Contact – objects must be touching Non-contact – objects do not need to touch
Define what a scalar quantity is.
A quantity with magnitude only
Give an example of a scalar quantity.
Speed, mass, distance
Define what a vector quantity is.
A quantity with magnitude and direction
Give an example of a vector quantity.
Velocity, force, displacement
What two properties do force arrows show?
Magnitude and direction
A tennis ball is dropped and falls to the floor. Name one contact and one non-contact force that acts on the ball.
Contact – air resistance/ drag Non-contact – gravity
Why are forces described as vector quantities?
They have magnitude and direction
Name two things that can happen when forces act on an object.
Change speed or direction
What is it called if the two forces are the same size and act in opposite directions?
Balanced
What 2 things can happen if the forces are the same size?
Stationary object remains stationary, Moving object maintains speed and direction
What 2 things can happen if the forces are not the same size?
Change speed, direction or shape
What is the resultant force?
Single force that replaces all the forces acting on an object.
If forces act along the same axis, how can resultant force be calculated?
By finding the difference between them
What is a vector diagram?
A diagram to show the overall single effect of forces
In physics, when is work done?
When a force moves an object
What two factors affect work done?
Force and distance
What is the word equation used to calculate work done?
Work done = Force x Distance
What are the units for work done?
Joules
One newton-metre is equal to how many joules?
1 Joule
What is the relationship between work done and energy transferred?
They are equal
What is weight?
The force of gravity acting on an object
What is the unit for weight?
Newtons
What is mass?
The amount of substance an object contains
What apparatus can be used to measure weight?
Newtonmeter
How is mass calculated?
Mass = Weight ÷ GFS
What is the value of GFS on Earth?
9.8 N/kg
What effect does decreasing weight have on mass?
Decreases mass
What force will act on a falling object?
Gravity
How do objects on Earth gain GPE?
Being raised above the ground
Give two reasons why books on a higher shelf have more GPE than books on a lower shelf
They have a greater mass and are higher up