M1 –Newton’s Laws of Motion and Connected Particles Summary
M1 –Newton’s Laws of Motion and Connected Particles Summary
 Newton’s first law: Every object remains at rest or moves with constant
velocity unless an external force is applied. I.e. If a particle moves with
constant velocity the resultant force will also be zero.
 Newton’s second law of motion: The resultant force acting on a body
produces an acceleration which is proportional to the resultant force. I.e.
F = ma where F is the resultant force in the direction of motion, m is
mass and a is acceleration.
 Newton’s third law: For every action there is an equal and opposite
reaction. I.e. if A pushes B then B pushes A with the same amount of
force in the opposite direction. These forces cancel out and do not affect
the acceleration of the system. They only become important when you
examine the acceleration of one object alone.
 Connected particles deal with two objects which are joined, usually by a
string, often passing over pulleys.
 Modelling assumptions for connected particles include light, inextensible
string that remains taut – thus the particles have the same acceleration,
and light, smooth and fixed pulleys – thus it does not affect the motion of
the particles and the tension is the same throughout the string.
 Always draw a force diagram for each particle separately
 Newton’s first law: Every object remains at rest or moves with constant
velocity unless an external force is applied. I.e. If a particle moves with
constant velocity the resultant force will also be zero.
 Newton’s second law of motion: The resultant force acting on a body
produces an acceleration which is proportional to the resultant force. I.e.
F = ma where F is the resultant force in the direction of motion, m is
mass and a is acceleration.
 Newton’s third law: For every action there is an equal and opposite
reaction. I.e. if A pushes B then B pushes A with the same amount of
force in the opposite direction. These forces cancel out and do not affect
the acceleration of the system. They only become important when you
examine the acceleration of one object alone.
 Connected particles deal with two objects which are joined, usually by a
string, often passing over pulleys.
 Modelling assumptions for connected particles include light, inextensible
string that remains taut – thus the particles have the same acceleration,
and light, smooth and fixed pulleys – thus it does not affect the motion of
the particles and the tension is the same throughout the string.
 Always draw a force diagram for each particle separately
Although not new in these chapters you need to remember
 If there is motion F = R, where F is friction,  is the coefficient of friction
and R is the normal reaction.
 The suvat equations
Although not new in these chapters you need to remember
 If there is motion F = R, where F is friction,  is the coefficient of friction
and R is the normal reaction.
 The suvat equations