Forces Flashcards
Name three types of forces
Contact, non-contact, reactant
Name three contact forces
friction, drag (air and water resistance), thrust, upthrust, tension and reaction
Name three non-contact forces
Gravitational, electrostatic and magnetic forces
How do you measure a force
With a forcemeter also called a newtonmeter
What unit is used to measure a force
Newton
Fill in the blanks: An arrow shows the ……….. of the force (the longer the arrow, the …… the force) and the …….. in which the force acts.
size, bigger, direction
Fill in the blank:
When two forces acting on an object are equal in size but act in opposite directions, we say that they are …… forces
balanced
The resultant force on a moving object is 0 Newton. What happens to the object?
It keeps moving at a steady speed in the same direction
The resultant force on a stationary object is 0 Newton. What happens to the object?
It stays still
Why does a boat float
A boat floats because its weight is balanced by the upthrust from the water
Fill in the blank:
The weight of a book lying on a table is balanced by the ……. force from the table top
Reaction
Fill in the blank:
If the forces on an object are unbalanced this is what happens:
- an object that is not moving ……….
- an object that is moving changes ………
starts to move
changes speed or direction
Fill in the blank:
When two forces acting on an object are unequal in size or do not act in opposite directions, we say that they are …… forces
Unbalanced
What is a resultant force
The size of the overall force acting on an object is called the resultant force.
What is the resultant force when the forces are balanced?
0 Newton
The thrust is moving a truck forward by 100N, the air resistance is pushing it backward by 40N. What is the resultant force and in which direction is the truck going.
60N forward.
Fill in the blank:
The weight of the leaf and the air resistance are …… The leaf falls at a steady speed.
Balanced
