Resultant Forces and Work Done Flashcards
Forces (18 cards)
What do free body diagrams show?
All the forces acting on an isolated object or system
They illustrate forces without showing the forces the object exerts on the rest of the world.
What forces act on a skydiver during free fall?
- Weight pulling him towards the ground
- Drag (air resistance) acting in the opposite direction to his motion
What does the size of the arrows in a free body diagram represent?
The magnitudes of the forces
What does the direction of the arrows in a free body diagram indicate?
The directions of the forces acting on the object
What is a resultant force?
The overall force on a point or object
How can multiple forces acting at a point be simplified?
They can be replaced with a single force that has the same effect as all original forces together
How do you calculate the resultant force when forces act along the same line?
Add forces in the same direction and subtract those in the opposite direction
What is the resultant force acting on an object if the vertical forces are 1500 N up and 1500 N down?
0 N
If horizontal forces are 1200 N to the right and 1000 N to the left, what is the resultant force?
200 N to the right
What happens when a resultant force moves an object?
Work is done and energy is transferred
What is required to make an object move against friction?
A force must be applied
What is a source of energy needed for applying force?
Fuel or food
What does ‘work is done’ mean?
Energy is transferred from one store to another
When pushing an object along a rough surface, what kind of energy transfer occurs?
- Kinetic energy to the object
- Thermal energy due to friction
What is the formula for calculating work done?
W = F × s
What does one joule of work correspond to?
A force of one newton causing an object to move a distance of one meter
How do you convert joules to newton meters?
1 Joule = 1 Newton meter (1 J = 1 Nm)
True or False: Work done and energy transferred are the same.
True
