Physics 30

1. VECTOR COMPONENTSVECTOR COMPONENTS
 Part of a vectorPart of a vector
 x-componentx-component: Determines how far: Determines how far
horizontallyhorizontally the vector is tiltedthe vector is tilted
 y-componenty-component: Determines how far: Determines how far
verticallyvertically the vector is tiltedthe vector is tilted

2. VECTOR COMPONENTSVECTOR COMPONENTS
x-component
y-componentA
In this case, both components
are positive

3. PROJECTILE MOTIONPROJECTILE MOTION
 ActsActs onlyonly under the influence ofunder the influence of
gravity (neglecting air resistance)gravity (neglecting air resistance)
 Follows a curved, 2-D pathFollows a curved, 2-D path

4. X-COMPONENTX-COMPONENT
 Neglecting air resistance, theNeglecting air resistance, the
horizontal velocity of a projectilehorizontal velocity of a projectile
remains constantremains constant

5. Y-COMPONENTY-COMPONENT
 The vertical component ofThe vertical component of
the velocity of a projectilethe velocity of a projectile
changes due to gravitychanges due to gravity
 The object acceleratesThe object accelerates
downwarddownward
 The y-component acts theThe y-component acts the
same as an object in freefallsame as an object in freefall

6. PROJECTILE MOTIONPROJECTILE MOTION
 These motions will combineThese motions will combine
to form a trajectory in theto form a trajectory in the
shape of a parabolashape of a parabola

7. PROJECTILE MOTIONPROJECTILE MOTION

8. PROJECTILE MOTIONPROJECTILE MOTION

9. PROJECTILE MOTIONPROJECTILE MOTION
 The horizontal component of aThe horizontal component of a
projectile isprojectile is entirely independententirely independent
from the vertical component offrom the vertical component of
motionmotion
 Changing oneChanging one does notdoes not affect theaffect the
otherother

10. PROJECTILE MOTIONPROJECTILE MOTION
 The equations of 1-D motion still applyThe equations of 1-D motion still apply
(refer to your formula sheet), but keep(refer to your formula sheet), but keep
uniform motionuniform motion distinct fromdistinct from uniformlyuniformly
accelerated motionaccelerated motion..
 DONDON’T MIX’T MIX x- and y-components in thex- and y-components in the
same equation. Keep them separate!same equation. Keep them separate!
 Time, however, is a scalar quantity.Time, however, is a scalar quantity.
 Time (and only time) can be used withTime (and only time) can be used with
both x- and y-componentsboth x- and y-components

11. PROJECTILE MOTIONPROJECTILE MOTION
 At the top of its path, an object hasAt the top of its path, an object has
zerozero y-component to its velocity.y-component to its velocity.
It movesIt moves
perfectlyperfectly
horizontallyhorizontally
for a slip-secondfor a slip-second
instant in timeinstant in time

12. PROJECTILE MOTIONPROJECTILE MOTION
 Neglecting airNeglecting air
resistance, theresistance, the
path of apath of a
projectile isprojectile is
perfectlyperfectly
symmetricalsymmetrical