GCSE- Forces and their effects Flashcards
What is an alternative name for the turning effect of a force?
A moment
State the equation used to calculate the moment of a force. Give appropriate units?
Moment of force= Force x distance
Moment (Nm), Force (N), Distance (m)
What distance measurement is used when calculating a moment?
The perpendicular distance from the pivot to the line of action of the force.
If an object is in equilibrium, what can be said about the moments acting on the object?
The clockwise moments are equal to the anticlockwise moments.
How do levers make use of Moments?
They increase the perpendicular distance of the forces from the pivot, so decrease the force needed to produce the same moment.
On a seesaw there is a force of 20N acting on the 2m side and on the other 4m side there is 10N acting on it. Will this object rotate? If so in which direction?
No. The clockwise and anticlockwise moments ae equal, therefore the object remains in equilibrium.
A block is put on one side of the seesaw and the other has a force acting on it. How are the levers used to decrease the force required to life something?
Levers use a pivot point and concept of moments to reduce the force. The further you are away from the pivot point the less force you need to lift the object up.
How does lubricating levers/ gears improve efficiency?
There is less resistance; less energy is wasted/ dissipated (as heat) overcoming frictional forces.
What is a balanced force?
A resultant force of zero.
What is a contact force
A force that acts on an object through physical contact.
What is an electric field?
A region where a charge will experience a non-contact electrostatic force.
What is equilibrium?
An object in equilibrium has a zero resultant force and a zero resultant moment.
What is a force field?
A region where an object will experience a non-contact force.
What is are force vectors?
An arrow that represents a force. The length represents the force’s magnitude and the arrowhead shows the direction in which it acts.
What is a free body diagram?
A visual representation of the forces that act on a object.
What is friction?
A resistive contact force that acts to oppose the relative motion between two surfaces.
What is a gear?
A simple mechanism that transmits the rotational effect of a force .
What is a gravitational field?
A region where a mass will experience a non-contact gravitational force.
What is a lever?
A simple mechanism that can transmit the rotational effect of a force.
What is lubrication?
The application of a lubricant (such as oil) to reduce the friction that acts between surfaces. This may improve the efficiency of a system.
What is a magnetic field?
A region where a magnetic material will experience a non-contact magnetic force.
What is a moment?
The turning effect of a force, equal to the product of the magnitude of the force and the perpendicular distance form the pivot to the line of action of the force.
What is a newton metre?
The unit of a moment.
What is a non-contact force?
A force that act on an object at a distance. There is no physical contact, instead the force acts through a field.
