Chapter 9 Flashcards
How do you work out the horizontal force when a force is applied at angle θ to the horizontal?
Fh=Fcosθ
How do you work out the vertical force when a force is applied at angle θ to the horizontal?
Fv=Fsinθ
Why are perpendicular forces independent of each other?
cos90=0. So forces that act at 90° to each other have no effect on each other.
Is force a vector or a scalar?
Vector.
What is Newton’s first law?
The velocity of an object will not change unless a resultant force acts on it.
What is Newton’s second law?
Acceleration is proportional to force. (F=ma)
Show that all objects fall at the same rate. (Ignoring air resistance)
F=ma=W=mg
ma=mg
a=g
What is Newton’s third law?
If an object A exerts a force on object B, then object B exerts an equal but opposite force on object A.
Momentum=
mv
What is the difference between elastic and inelastic collisions?
A perfectly elastic collision is one where momentum and kinetic energy are conserved. An inelastic collision is one where momentum is conserved but some kinetic energy is converted into other forms.
What is impulse?
Impulse is the change in momentum of one object. (Ft)
What are the two main types of friction and what are they?
Contact Friction-Between two surfaces.
Fluid Friction-With liquid/gas.
What does friction convert kinetic energy into?
Thermal energy.
List 4 things that can affect the terminal velocity of an object.
Viscosity of the liquid, size, shape and mass of the object.
Work (J)=
Force x Distance
