Transcript Forces Chapter 10 - Powers Physical Science

Forces Chapter 10
What is an example of exerting
force?
Pushing/pulling anything
What happens when two forces act
in the same direction?
They add together
The force of gravity on a person
or object on the surface of a
planet is called
Friction
Which of the following is an
example of rolling friction?
Anything rolling
When the only force acting on a
falling object is gravity, then the
object is said to be
In free fall
Air resistance is a type of
Friction
The law of universal gravitation
states that any two objects in
the universe, without exception
Attract each other
In physical science, a push or a pull
is called a
Force
The amount of matter in an object
is called its
Mass
Which of the following is an
example of increasing friction
intentionally
Throwing sand on an icy driveway
The force that pulls falling objects
toward Earth is called
Gravity
Objects falling through air
experience a type of friction called
Air resistance
The SI unit for force is the
Newton
Balanced forces acting on an
object
Never change the object’s motion
The tendency of an object to resist
change in its motion is known as
Inertia
How can you increase the
momentum of an object?
By increasing mass or velocity
According to the law of
conservation of momentum,
when two objects collide in the
absence of friction,
Momentum is transferred and not
lost
The total momentum of a group of
objects is conserved unless
Outside forces act on the objects
According to Newton’s third law
of motion, when a hammer
strikes and exerts force on a
nail, the nail
Exerts an equal force on the
hammer
What happens when a unbalanced
force acts on an object?
The objects in motion will
accelerate
Which of these objects would
exhibit the greatest resistance
to a change in it’s motion?
Heaviest mass
Newton’s second law of motion
states the relationship of mass,
acceleration, and force. It says
that
F = Mass x Acceleration
As the force applied to the
object is increases, the objects
will also increase.
Acceleration
A 300 N force acts on a 20 kg
object. The acceleration of the
object is
15 meters per second squared
Compared to a sports car
moving at 30 mph, the same
sports car moving at 60 mph
has
Twice as much momentum
One way to increase acceleration is
by
Decreasing mass,
Increasing force
The product of an object’s mass
and velocity is called its
Momentum
A person standing on roller
skates is holding a heavy rock.
If he throws the rock horizontally
to the right, what will be his
resulting motion?
To the left
The amount of gravity between
two objects depends on their
masses and
Distance between them
Forces can be added together only
if they are
Acting in the same direction
A student pushes a lawnmower
with a force of 15 N. What is the
force exerted by the mower on
his hands?
15 N
The momentum of an object is in
the same direction as its
Velocity
What happens when two forces act
in the same direction?
Added together
That force that one surface
exerts on another when the two
rub against each other is called
Friction
Mass times acceleration equals
the net force acting on an object
according to which of Newton’s
laws?
2nd Law
Which has more momentum, a
semi-truck moving at 30 mph or
a Chevy S10 truck moving at 30
mph?
Semi-truck
The greater the mass of an object,
The greater the inertia
Balanced forces acting on an
object
Never change object’s motion