Paper 1, Topic 2 - Mechanics Flashcards
How do you resolve vectors?
Split the vector into its horizontal and vertical components
What is the Equation of a moment?
Moment(Nm) = Force(N) x Perpendicular distance (m)
When are moments in equilibrium?
When total Clokwise Moment = Total Anticlockwise Moment
When talking about moments, what is a couple?
A pair of equal and opposite parallel forces that both act on the same body and do not act in the same line.
What is the moment of a couple (Nm) ?
Force (N) x Perpendicular Distance Between Lines of Action (m)
What is the centre of mass?
Where the mass of the object can be considered to be concentrated.
How do you find the centre of mass of an object?
Hang the object from a pivot and use a plum line to draw a line of action.
Hang the object again at a different point then again use a plum line to draw a line of action.
The centre of mass is where the two lines intersect.
What is Newton’s first law?
An object will remain in its stationary or moving state unless acted on by a resultant force.
What is Newton’s second law?
Force (N) = Mass (kg) x Acceleration (ms⁻²)
What is Newton’s second law?
Every action has an Equal and Opposite reaction.
What are two equations for work done?
Power = ΔW / Δt Power = Fv
What is the equation for Work?
W = Force x Distance x cosθ
What are two equations for efficiency?
Efficiency = Useful power output / Total power input
Efficiency = Useful energy output / Total energy input
What is the equation for momentum?
Momentum (kgms⁻¹) = Mass (kg) x Velocity (ms⁻¹)
When is the conservation of momentum always observed?
In a closed system when there are no external forces.
What is an elastic collision?
A collision in which kinetic energy is conserved.
What is an inelastic collision?
A collision in which kinetic energy is not conserved.
What are the equations for Impulse?
Impulse = F x Δt =Δ(m x v)
What is the definition of Impulse?
The change of momentum of an object.
How do you work out impulse on a Force-Time graph?
Impulse is equal to area under the graph.
