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Forces and MotionForces and Motion
2013 M.B. Pardington, BPS
A force is a…
PUSH PULL
A force can change the motion of an object.
SPEED
DIRECTION
A force can change the motion of an object.
An additional force in the same direction increases the speed
of the object.
Push Push + Push
An additional force in the same direction increases the speed
of the object.
Push Push + Pull
An additional force in the same direction increases the speed
of the object.
Pull Pull + Pull
Opposing forces of equal magnitude acting on an object produce no change in motion.
5 N vs. 5 NCart doesn’t move.
Opposing forces of equal magnitude acting on an object produce no change in motion.
5 N vs. 5 NCart doesn’t move.
Opposing forces of unequal magnitude acting on an object result in a change in motion.
3 N Pull + 5 N Push
NET FORCE 2 N PUSH to the
RIGHT
A change in motion is described as a change in speed
and/or direction of an object.
3 N Pull + 5 N Push
NET FORCE 2 N PUSH to the
RIGHT
BALANCED FORCEA force must be A force must be
balancedbalanced in order to in order to achieve achieve constantconstant speed. speed.
UNBALANCED FORCE
A force must be A force must be unbalancedunbalanced (nonzero net force) in order (nonzero net force) in order
for an object to change for an object to change speed and/or direction.speed and/or direction.
20 N
40 N
UNBALANCED FORCE
A force must be A force must be unbalancedunbalanced (nonzero net force) in order (nonzero net force) in order
for an object to change for an object to change speed and/or direction.speed and/or direction.
20 N
50 N
30 N
UNBALANCED FORCEA change in the mass of the A change in the mass of the object will result in a change object will result in a change in speed and/or direction of in speed and/or direction of the object. Compare these 3 the object. Compare these 3
carts.carts.
UNBALANCED FORCEA change in the mass of the A change in the mass of the object will result in a change object will result in a change in speed and/or direction of in speed and/or direction of the object. Compare these 3 the object. Compare these 3
carts.carts.
UNBALANCED FORCEA change in the mass of the A change in the mass of the object will result in a change object will result in a change in speed and/or direction of in speed and/or direction of
the object. Compare these 3 the object. Compare these 3 carts.carts.
SpeedSpeed is the ratio of Speed is the ratio of
distance covered per unit distance covered per unit of time.of time.
Speed = distance / timeSpeed = distance / time
The cart moved 6 meters per 3 seconds
Speed
The cart moved 6 meters per 3 seconds
Mathematically, that’s 6 / 3 or 6 ÷ 3which equals 2.
So, the cart moved 2 meters per secondor 2 m/sec
FORCE
CONTACTCONTACT NON-NON-CONTACTCONTACT
Contact Force
Contact Force
A contact force contact force is a push or pull that
directly touches the object..
FrictionFriction is a contact force exerted between objects such as:
AIR OBJECTS
WATER
Non-Contact Forces
GRAVITY
MAGNETISM
ELECTRICALCHARGES
Non-Contact Forces
These are pushes and pulls from a distance.
GravityGravityGravity is a force of
attraction between any mass and the matter
near it. The larger the mass of an object, the
greater the gravitational force it exerts on other
objects. For objects For objects on Earth, the pull of on Earth, the pull of
the Earth is the the Earth is the strongest force strongest force acting on them.acting on them.
Gravity““Jupiter is the most Jupiter is the most
massive planet in our massive planet in our Solar System and; Solar System and;
therefore, the therefore, the gravity gravity of Jupiter is the most of Jupiter is the most
intense in the Solar intense in the Solar system. Its system. Its
gravitational pull gravitational pull is is 2.5 times what is 2.5 times what is
here on Earth.”here on Earth.”
http://www.universetoday.com/15110/gravity-of-jupiter/
Gravity
Magnetism
N NS S
Here are “like” charges. Are they showing an attraction or are they
repelling?
Magnetism
N NS S
They are repelling.
Magnetic Repulsion
Magnetism
N NS S
Here are “unlike” charges. Are they showing an attraction or are they
repelling?
Magnetism
N NS S
They are showing an attraction.
Magnetic Attraction
Magnetism
N NS S
The attracting and repelling magnetic forces illustrate non-contact forces.They pull and push without contact.
N NS S
Electrical Charges
The attracting and repelling electrical forces illustrated in
the wind sock demonstration show non-contact forces.They push without
contact.
Bibliographyhttp://powerup.ukpowernetworks.co.uk/media/22576/78.jpg
http://www.clipart.dk.co.uk/DKImages/science/image_science010.jpg
http://www.clipart.dk.co.uk/DKImages/science/image_science009.jpg
http://www.universetoday.com/15110/gravity-of-jupiter/
http://www.mikecurtis.org.uk/images/friction.jpg
http://lvp.lockyersmid.dorset.sch.uk/pluginfile.php/3230/mod_resource/content/0/content/pictures/physical/keyideas/phpkey0005.jpg
http://www.united-states-flag.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/F/L/FLGBDEC1000003637_-00_st-patricks-wind-sock_4.jpg