Download Ch. 11.3

Chapter 11.3
Newtons
rd
3
law
Newton’s Laws
• 1. An object in motion or rest remains
the same unless acted on by a force.
• 2. Force= mass x acceleration.
The amount of force needed to move
an object is equal to the amount of
mass in the object and how much you
want to accelerate it.
• 3. For every action there is an =
and opposite reaction
Newton’s 3rd Law
• If you push on an object, gravity
and friction pull back on it. The
forces act in pairs but always in
opposite directions
• Forces do not act on
the same object
rd
3
law continued
• The forces may be happening
at the same time but may not
have equal effects.
Example a bouncing
ball never rebounds
as high as tossed
down.
• Action/reaction is everywhere.
Momentum
• Momentum is how
fast an object moves
due to its mass.
• A semi has more
momentum than a
Vw bug.
• To have momentum
you must be moving
Momentum con’t
• Formula for momentum
• p=mv (p stands for
momentum, m stands
for mass, and v stands
for velocity
• It takes force to change
Momentum
Momentum con’t
• Momentum is conserved or
saved. It is always transferred.
EX: You can transfer it to heat
in friction when you brake or
you can push a car forward
when you hit it.