Flashcards in Mechanics Deck (49)
What property does a scalar quantity have?
What properties do vectors have?
Both magnitude and direction.
Examples of vector quantities:
Velocity, displacement, acceleration, forces, momentum, weight, moments.
Examples of scalar quantities:
Speed, distance, electrical power, charge, mass, energy, current, potential difference.
...rate of change of distance.
...rate of change of displacement.
...rate of change of velocity.
Equation for acceleration using velocities:
What is unit acceleration measured in?
The gradient of a velocity time graph represents what?
The area under a velocity time graph represents what?
Define a moment.
The turning effect of a force at a distance perpendicular to the force.
Equation for moments:
M = Fd
M is the moment.
F is the force.
d is the distance perpendicular to the force from the pivot.
Moments are measured in what?
Centre of mass is what?
The mean position of the mass of an object.
Centre of gravity is what?
The position at which weight acts if the object is considered as a single position; the point at which there is no moment due to weight.
In a uniform gravitational field, what can be said about the centre of mass and the centre of gravity?
They are in exactly the same place.
An object is stable, when?
If the line of action from the centre of gravity lies within the base of the object.
How can an object be made more stable?
An object can be made more stable by lowering the centre of gravity or by widening the base.
What is the principle of moments?
A system can be said to be in equilibrium if the sum of the total anticlockwise moments equals the sum of the total clockwise moments.
What equipment can be used to find the centre of gravity of an object?
Equation for kinetic energy:
Ek = 1/2 mv^2
Equation for gravitational potential energy:
ΔEp = mgΔh
Elastic potential energy equations:
Eel = 1/2 Fx
Eel = 1/2 kx^2
Equation for work done:
W = Fscosϴ
What can a vector be resolved into?
A horizontal component and a vertical component.
How do we resolve to find horizontal and vertical components of vectors?
Sine to find the vertical component.
Cosine to find the horizontal component.
What does SUVAT stand for?
S for displacement/m.
U for initial velocity/ms^-1
V for final velocity/ms^-1
A for acceleration/ms^-2
T for time/s
What are the four equations of motion?