Download - Mechanical Rate (a.k.a. Motion)
Mechanical Rate(a.k.a. Motion)
http://www.uhigh.ilstu.edu/tech/PT/
TEKS• TLW knows the laws governing motion (TEKS
5)• TEKS 5.A - Analyze examples of uniform and accelerated
motion – including linear, projectile, & circular
• TEKS 5.B - Generate and interpret graphs describing motion including the use of real-time technology
• TEKS 5.C – Formulate the effects of forces on motion of objects
• TEKS 5.D – Develop and interpret a free-body diagram for force analysis
• TEKS 5.E – Identify and describe motion relative to different frames of reference
Lesson Plan Objectives
• Identify and describe motion relative to different frames of reference – such as heights and orbits
• Use real-time technology (photo-gates, ramps, stop watchers, etc.) in hands-on labs
• Prepare and interpret graphs from data collected on linear, projectile, and circular motion
• Define Speed, velocity, and acceleration.• Explain the difference between speed and velocity.• Explain the difference between velocity and acceleration.• Use speed, velocity, and acceleration to solve problems involving
linear (one-dimensional) motion.
Lesson Plan Objectives
• Use speed, velocity, and acceleration to solve problems involving projectile motion
• Define angular speed and angular acceleration.
• Use angular speed and angular acceleration to solve problems involving rotational motion.
• Create and use free-body diagrams to analyze force scenarios
Speed
• Speed is the ratio between the distance traveled and the elapsed time. (scalar quantity)
Distance traveled (d)
Time interval (t)Speed =
Examples of units to use: m/sec, km/hr, ft/sec, or miles/hr
Average Speed• When speed varies between point A and B
Distance traveled (d)
Time interval (t)
Average Speed
=
d
t
savg = =d2 – d1
t2 –t1
d2 = final distance (df) d1 = initial starting point (di)t2 = final time (tf) t1 = initial time (ti)
Velocity• A vector quantity giving the speed
(magnitude) and direction of travel.
displacement
timeVelocity =
d
tvavg =
Acceleration• Describes the rate of change of an object’s velocity
Velocity change (v)
Time interval (t)
Average
Acceleration =
v
t
aavg = =v2 – v1
t2 –t1
Negative acceleration is called deceleration
v2 = final velocity (vf) v1 = initial velocity (vi)t2 = final time (tf) t1 = initial time (ti)
Projectile Motion
Angular Speed
• Rate of rotational motion.
angular displacement ()
time interval (t) () =
Angular
Speed omega
1 revolution = 360º = 2 radians
radians or revolutions
Angular Acceleration• Ration of the change in angular speed to the
time interval.
Angular speed change ()
Time interval (t)
Angular
Acceleration =
ta = =
2 – 1
t2 –t1
Summary• Speed is a measure of the rate of motion of an object. It is the ratio of
distance traveled to the time interval. Speed is a scalar quantity.• Velocity is the ratio of displacement to the time interval. Velocity and
displacement are vector quantities. Speed is the magnitude of velocity.• Acceleration is a measure of the rate of change of an object’s velocity.
It is the ratio of change in velocity to the time interval.• Angular speed is a measure of the rate of rotational motion of an object.
It is the ratio of angular displacement to time interval.• Angular acceleration is a measure of the rate of change of an object’s
angular speed. It is the ratio of change in angular speed to the time interval.