Transcript Speed and Velocity

Speed and Velocity
F 10-14
• You are moving when you are changing position;
position is the location of an object
• Speed how fast an object position is changing
with time at any moment; you can find speed by
dividing the distance by the time
– Example: miles per hour or feet per second
– You can tell how fast a plane is moving by the
movement of its shadow
• Velocity the speed of a moving object taken
together with the direction of travel
– the velocity of an air craft carrier might be 40
kilometers/hour due south
• 2 objects can have the same speed but different
velocities if they are traveling in different
directions
– they can also have different velocities if they are
traveling in the same direction but at different speeds
– the only way to have the same velocity is if 2 objects
are traveling at the same speed in the same direction
• As long as an object travels in a straight
line at a steady speed; its velocity is
constant (Newton’s First Law tells us this)
• Acceleration a change in velocity;
Newton realized that applying a force to an
object would overcome its inertia and
change its velocity; causing it to accelerate
(example: pushing the gas pedal; the
mechanical swings at King’s Island)
• Deceleration a special case of
acceleration that occurs when a force
causes the speed of an object to decrease
(Example: the use of a parachute)
• An object moving in a circle is constantly
changing direction, so its velocity is
constantly changing. That means it’s
accelerating. A force is needed to
accelerate an object.