P8: Forces In Balance Flashcards
What does scalar mean?
Scalar quantities have only magnitude (size).
What does vector mean?
A vector quantity contains both direction and magnitude.
Give an example of a vector.
Velocity
Force
Displacement (m)
Momentum (kgm/s)
Give an example of a scalar.
Speed
Time
Distance
Mass
A force is an operation that causes an object to:
Change direction
Change force
Change speed
What are the five contact forces?
Frictional
Tension
Reaction
Air
Spring
What are the 3 non-contact forces?
Magnetic
Electrical
Gravitational
What is force measured in?
Newtons
Is gravity a force?
No
If the resultant force on an object is 0…
The object is either stationary or moving at a constant speed.
What is mass?
A measurement of all the matter (stuff) an object is made up of.
What is weight?
The force an object has on another body
What is mass measured in?
Kg or g
What is weight measured in?
Newtons
What is the equation linking weight and mass?
Wright = mass x gravitational field strength
What is gravitational field strength measured in?
N/Kg or m/s ^2
When do balanced forces occur?
When more than one force acts on an object and they are equal in size and opposite in direction.
Unbalanced forces acting on an object will cause _____.
Acceleration
What is a resultant vector?
The vector that results from the addition of two or more vectors in a vector sum.
What is the law of moments?
For an object to be in equilibrium (balance), the clockwise moments must be equal to the anti-clockwise moments.
What is the equation for moments?
M=Fxd
What is the units for moments?
Nm
What is the centre of mass of an object?
The point at which its mass can be thought of as being concentrated.
What is suspended equilibrium?
when the centre of mass is directly below the point where it is suspended.
Why are gears used?
Is are used to increase the turning affect (moment), they do this by increasing the distance to the pivot (same as radius of the gear).
