Mastering Kinematics: From Fundamental to Derived Quantities
Delve into the world of physics kinematics, exploring fundamental and derived quantities, significant figures, scientific notation, measurement tools, accuracy, precision, velocity, acceleration, and uniformly accelerated motion.
Mastering Kinematics: From Fundamental to Derived Quantities
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Presentation Transcript
Physics Beyond 2000 Chapter 1 Kinematics
Physical Quantities • Fundamental quantities • Derived quantities
Fundamental Quantities http://www.bipm.fr/
Derived Quantities • Can be expressed in terms of the basic quantities • Examples • Velocity • Example 1 • Any suggestions?
Derived Quantities • More examples
Standard Prefixes • Use prefixes for large and small numbers • Table 1-3 • Commonly used prefixes • giga, mega, kilo • centi, milli, micro, nana, pico
Significant Figures The number of digits between the Most significant figure and least significant figure inclusive. • The leftmost non-zero digit is the most significant figure. • If there is no decimal point, the rightmost non-zero digit will be the least significant figure. • If there is a decimal point, the rightmost digit is always the least significant figure.
Scientific Notation • Can indicate the number of significant numbers
Significant Figures • Examples 5 and 6. • See if you understand them.
Significant Figures • Multiplication or division. • The least number of significant figures. • Addition or subtraction. • The smallest number of significant digits on the right side of the decimal point.
Order of Magnitude • Table 1-4.
Measurement • Length • Meter rule • Vernier caliper • Micrometer screw gauge Practice
Measurement • Time interval • Stop watch • Ticker tape timer • Timer scaler
Measurement • Mass • Triple beam balance • Electronic balance
Measurement • Computer data logging
Error Treatment • Personal errors • Personal bias • Random errors • Poor sensitivity of the apparatus • System errors • Measuring instruments • Techniques
Accuracy and Precision • Accuracy • How close the measurement to the true value Precision • Agreement among repeated measurements • Largest probable error tells the precision of the measurement
Accuracy and Precision • Examples 9 and 10
Accuracy and Precision • Sum and difference • The largest probable error is the sum of the probable errors of all the quantities. • Example 11
Accuracy and Precision • Product, quotient and power • Derivatives needed
Kinematics • Distance d • Displacement s
Average Velocity • Average velocity = displacement time taken
Instantaneous Velocity • Rate of change of displacement in a very short time interval.
Uniform Velocity • Average velocity = Instantaneous velocity when the velocity is uniform.
Speed • Average speed • Instantaneous speed
Speed and Velocity • Example 13
Relative Velocity • The velocity of A relative to B • The velocity of B relative to A
Relative Velocity • Example 14
Acceleration • Average acceleration • Instantaneous acceleration
Average acceleration • Average acceleration = change in velocity time Example 15
Instantaneous acceleration Example 16
v t Velocity-time graphv-t graph Slope: = acceleration
v-t graph • Uniform velocity: slope = 0 v t
v-t graph • Uniform acceleration: slope = constant v t
Falling in viscous liquid Acceleration Uniform velocity
Falling in viscous liquid v uniform speed: slope = 0 acceleration: slope=g at t=0 t
Bouncing ball with energy loss Let upward vector quantities be positive. Falling: with uniform acceleration a = -g.
v-t graph of a bouncing ball • Uniform acceleration: slope = -g v t falling
Bouncing ball with energy loss Let upward vector quantities be positive. Rebound: with large acceleration a.
v-t graph of a bouncing ball • Large acceleration on rebound v rebound t falling
Bouncing ball with energy loss Let upward vector quantities be positive. Rising: with uniform acceleration a = -g.
v-t graph of a bouncing ball • Uniform acceleration: slope = -g v rebound rising t falling
v-t graph of a bouncing ball The speed is less after rebound • falling and rising have the same acceleration: slope = -g v rebound rising t falling
Linear Motion: Motion along a straight line • Uniformly accelerated motion: a = constant velocity v u time 0 t
Uniformly accelerated motion • u = initial velocity (velocity at time = 0). • v = final velocity (velocity at time = t). • a = acceleration v = u + at
Uniformly accelerated motion • = average velocity velocity v u time 0 t
Uniformly accelerated motion s = displacement = velocity v u time 0 t s = area below the graph
Uniformly accelerated motion • Example 17
Free falling: uniformly accelerated motion Let downward vector quantities be negative a = -g