PHY 111 Exam 2 Questions with Verified
Correct Answers
Force
A push or pull that can change and objects motion; force is a vector with magnitude and
direction
Net Force
The vector sum of all forces acting on an object; ΣF
Newtons First Law
An object remains at rest or moves with constant velocity unless acted on by a net external
force
Newtons Second Law
The net force on an object equals its mass * its acceleration; ΣF = ma
Newtons Third Law
For every force exerted by o object on another, there is an equal and opposite force exerted
back; F(A→B) = −F(B→A)
Inertia
An object's resistance to changes in its motion; greater mass = greater inertia
Equilibrium
A situation in which the net fore is zero and acceleration is zero
Static Equilibrium
An object is at rest with zero acceleration
, Dynamic Equilibrium
An object moves with constant velocity and has zero acceleration
Acceleration and net force
Net force causes acceleration; if ΣF ≠ 0, then a ≠ 0
Zero net force
f ΣF = 0, then acceleration is zero; the object may be at rest or moving at constant velocity.
Weight
The gravitational force acting on an object; Fg = mg
Mass
The amount of matter/inertia of an object; measured in kg
Gravity
The attractive force between masses; near earths surface, Fg = mg and points downward
Gravitational Acceleration
Near Earth's surface, g ≈ 9.8 m/s² downward
Normal Force
A contact force exerted by a surface perpendicular to the surface
When does FN=mg
For an object on a horizontal surface with no vertical acceleration and no other vertical forces
Tension
A pulling force exerted by a rope, string, or cable; it acts along the rope
Correct Answers
Force
A push or pull that can change and objects motion; force is a vector with magnitude and
direction
Net Force
The vector sum of all forces acting on an object; ΣF
Newtons First Law
An object remains at rest or moves with constant velocity unless acted on by a net external
force
Newtons Second Law
The net force on an object equals its mass * its acceleration; ΣF = ma
Newtons Third Law
For every force exerted by o object on another, there is an equal and opposite force exerted
back; F(A→B) = −F(B→A)
Inertia
An object's resistance to changes in its motion; greater mass = greater inertia
Equilibrium
A situation in which the net fore is zero and acceleration is zero
Static Equilibrium
An object is at rest with zero acceleration
, Dynamic Equilibrium
An object moves with constant velocity and has zero acceleration
Acceleration and net force
Net force causes acceleration; if ΣF ≠ 0, then a ≠ 0
Zero net force
f ΣF = 0, then acceleration is zero; the object may be at rest or moving at constant velocity.
Weight
The gravitational force acting on an object; Fg = mg
Mass
The amount of matter/inertia of an object; measured in kg
Gravity
The attractive force between masses; near earths surface, Fg = mg and points downward
Gravitational Acceleration
Near Earth's surface, g ≈ 9.8 m/s² downward
Normal Force
A contact force exerted by a surface perpendicular to the surface
When does FN=mg
For an object on a horizontal surface with no vertical acceleration and no other vertical forces
Tension
A pulling force exerted by a rope, string, or cable; it acts along the rope
