# Motion

Μηχανική

14 Νοε 2013 (πριν από 4 χρόνια και 7 μήνες)

139 εμφανίσεις

Unit 1

Motion

Projectile

Motion

Motion to Date

Uniform Motion

Accelerated Motion

Relative Motion

Uniform Motion

Motion with a constant velocity

Equation:

d
v
t

-

Constant speed

-

Same direction

Problems

1. An airplane travels 300 km in 1.25
hours. Find its speed.

2. A hunter travels 3 km [N] in 0.75 h
and 2 km [E] in 30 minutes. Find
her average:

A) speed

B) velocity

3.

A kayaker can travel at 4 m/s relative to
the water.

If she is in a river that has a current of 2
m/s [S] find her velocity with respect to
(wrt) the (i) shore and (ii) water

A) Upstream

B) Downstream

C) Directly across the stream

Applet

VECTOR REVIEW??

http://hyperphysics.phy
-
astr.gsu.edu/hbase/vect.html

Suppose the river is 50 m wide. How
far will the kayak land downstream
on the other side?

4.

Suppose the kayaker want to land
directly across the stream.

A) Find the angle she would have to point to
do so.

B) Find the time it would take for her to get
to the other side.

Accelerated motion

Motion with changing velocity

Examples?

Accelerated motion occurs when
either

the speed is changing

speeding up or slowing down

Direction is changing

Curved motion

Equations for accelerated motion

Page 56 text

Formula Sheet

Examples

1.

A cyclist can accelerate from 10.
km/h to 30. km/h in 3.5s. Find his
acceleration.

2.

A glove is dropped from a chairlift
and hits the ground 2 seconds later.

A)

How high is the chairlift?

B)

How fast was the glove travelling
when it hit the ground?

3.

Police measure skid marks to
determine the speed of a car just
before skidding started. If the
acceleration of car is 7.5 m/s
2

(based
on the surface condition of the road)
and the length of the skid is 45 m,
determine the speed the car was
traveling before locking the tires.
(Assuming the car was stopped at
the end of the skid.)

4.

Determine the speed the object
hits the ground.

100 m

The object has an initial upwards velocity

of 25 m/s.

5.

Determine the time it would take a
rock to hit the ground if:

A) it was dropped from a height of 2 m.

B) thrown upwards at 20 m/s from the
2 m height.

C) thrown downwards at 20 m/s from
the 2 m height.

Page 74

#
54, 55, 65, 66

What is projectile motion?

Anything that is thrown that has
some
_____________
motion.

Jumping on a
_____, ___, __________,
_________
, skakeboards, __________,
horses, ______.

Running off a
________________
.

_____________________

that are shot.

Throwing
__________

or
___________
,
or kicking a
______________
.

A projectile is any object which, once
projected, continues its motion by its
own
________

and is influenced only
by the downward force of
________
.

It is important to study this if you
want objects to land in certain spots

Movie 1

Movie 2

What describes the path of a
projectile?

__________________

In 3204 projectile motion is limited
to negligible
_____________

otes/projectile/projectile.html

Mythbusters

Horizontal motion (
__
-
direction) is
____________

(no
_____________
)

Vertical motion (
__
-
direction) is
_______________

(
____________
)

Distance travelled in the x
-
direction
is defined as
________.

Time is the
______

in both the x and
y direction.

Equations for Projectile Motion

Horizontal Motion

(x
-
direction)

Uniform Motion

Vertical Motion

(y
-
direction)

Accelerated Motion

Components of Velocity

Mathematically determine the
components of velocity at certain
points along a projectile’s motion.

Applet

Types of Projectile Motion

_______________

moving off a cliff

(
_____________________
)

Projected motion at
____________
,
and lands at a point

Projected motion at an angle
q
, and
lands at a point:

A) level with launch

B) Above launch

C) below launch

Projectiles with zero vertical
velocity

Worksheet 1

Projectiles with NON zero vertical
velocity

Worksheet 2

Worksheet 3

Assignment

The Physics of Juggling

Applet

Air resistance

Page 74
-
75

#54.

2
1
2
d at

2
d
t
a

2
2(553 )
9.80/
m
t
ms

The time is 10.6 s.

#55.

2
1
1
2
d vt at
 
#65.

#66.

Back