Physical Science Unit 1 Motion

Mass Amount of matter in an object Units: kilogram (or gram) Measured: Using a balance

Volume Amount of space taken up by an object Units: m3 or ml Measured: Regular object: length X width X height Irregular object: water displacement

Density Ratio of an object’s mass to its volume Units: kg/m3 Calculated: Density=mass/ volume

Density = Mass/ Volume 1. What is the density of carbon dioxide gas if .196g occupies a volume of 100ml? 2. A block of wood 3.0 cm on each side has a mass of 27 g. What is the density of this block? 3.An irregular shaped stone was lowered into a graduated cylinder holding a volume of water equal to 2.0mL. The height of the water rose to 7.0mL. If the mass of the stone was 25g, what was its density?

4. A 10. 0cm3 sample of copper has a mass of 89. 6g 4. A 10.0cm3 sample of copper has a mass of 89.6g. What is the density of copper? 5. Silver has a density of 10.5 g/cm3 and gold has a density of 19.3 g/cm3. Which would have a greater mass, 5 cm3 of silver or 5 cm3 of gold? 6. Five ml of ethanol has a mass of 3.9 g, and 5.0 ml of benzene has a mass of 4.4g. Which liquid is denser? 7. A sample of iron has the dimensions of 2cm X 3cm X 2cm. If the mass of this rectangular shaped object is 94 g, what is the density of iron?

States of Matter Solids- have a definite shape and volume Atoms are packed close together in a regular pattern Liquids- definite volume but shape may change Atoms are close together but their arrangement is more random Gases- no definite volume or shape Atoms are arranged randomly with more space between them. Plasma- exists at very high temperatures

Kinetic Theory States that all particles of matter are in constant motion Solids Particles vibrate around fixed locations; no visible motion Liquids Liquid takes shape of its container because atoms can flow but they maintain their volume because the forces of attraction keep the particles close together Gases Particles in a gas are in constant, random motion Motion of one particle is unaffected by the motion of other particles unless the particles collide. Forces of attraction can be ignored under ordinary conditions.

Factors that affect pressure Result of a force distributed over an area Unit: Pa (pascal); N/m2 Temperature Average amount of kinetic energy Factors that affect pressure Raising temperature will increase the pressure (increase motion) Volume- reducing volume increases pressure

Gas Laws Charles’s Law Boyle’s Law Volume of a gas is directly proportional to its temperature If temperature increases, volume increases V1/T1= V2/ T2 Boyle’s Law Volume of a gas is inversely proportional to its pressure If volume decreases pressure increases P1V1= P2V2

Phase Diagrams Lets you work out which exact phases are present at any give temperature and pressure Melting- from solid to liquid Freezing- from liquid to solid Vaporization- from liquid to gas Condensation- from gas to liquid Sublimation- from solid to gas Deposition- from gas to solid

Phase Change Draw a phase change diagram. Be sure to include the following: solid, liquid, gas, temperature, pressure. On the phase diagram, label the 6 phase changes.

Distance and Displacement Frame of Reference Relative Motion Movement based on frame of reference Distance Length of a path between two points SI unit is meter (m); may use km or cm

Speed And Velocity Speed- how fast an object moves Speed= distance/time SI unit of speed is m/s Constant speed- doesn’t change Average speed- speed varies (distance divided by time) Velocity- describes both the speed and direction of a moving object

Practice Speed and Velocity A ship travels 200 km in 4 hours. Calculate the velocity. A horse began running due east and covered 25km in 5 hrs. What is the average velocity of the horse? What is the velocity in meters per second of a runner who runs exactly 110 m toward the beach in 72 seconds?

Speed Speed can be determined using a graph on which distance is plotted at various times Slope is a measure of steepness The faster the speed of an object, the greater the slope of the line on its distance vs. time graph When speed =0 or object is not moving, the line is horizontal

Acceleration The rate at which velocity changes Can be a change in direction and/or speed Calculating acceleration Acceleration= change in velocity/ total time

Graphs of Acceleration The slope of a speed- time graph is acceleration. Positive Acceleration Negative Acceleration

Practice Acceleration A car accelerates from 0m/s to 45 m/s northward in 15 s. What is the acceleration of the car? After reaching 45 m/s, the car slows down to 0 m/s in 10.0s. What is the acceleration of the car?

Force Push or pull that acts on an object SI unit= Newton (N) Or 1kg*m/s2 An arrow can be used to represent strength and direction of force

Combining Forces Balanced Forces Unbalanced Forces Forces can be added together; creates net force  = --------> Balanced Forces The overall net force is zero  =0 Unbalanced Forces Causes movement in the direction of the greater force -------- = ---

Friction Force that opposes motion of objects as they move past each other Four basic kinds Static Sliding Rolling Fluid Air resistance Gravity Force that acts between two masses

Newton Newton’s 1st Law of Motion Newton’s 2nd Law of Motion An object at rest stays at rest and an object in motion remains in motion unless it experiences an unbalanced force. Law of inertia Newton’s 2nd Law of Motion Acceleration of object is equal to the net force acting on it divided by the object’s mass. Acceleration= net force/ Mass or a=F/m

Practice Problems An automobile with a mass of 1000 kilograms accelerates when the traffic light turns green. If the net force on the car is 4000 N, what is the car’s acceleration? A boy pushes forward a cart of groceries with a total mass of 40.0 kg. What is the acceleration of the cart if the net force on the cart is 60.0 N? An automobile with a mass of 1200kg accelerates at a rate of 3.0 m/s2 in the forward direction. What is the net force acting on the automobile?

Weight and Mass Weight is the force of gravity acting on an object Weight= mass X acceleration due to gravity W=mg (g= 9.8m/s2) Mass is a measure of the inertia of an object Unit for weight is N Unit for mass is Grams Astronaut on Earth Mass= 88kg; Weight= 863 N Astronaut on Moon Mass = 88kg; Weight= 141N

Newton’s 3rd Law When one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object. (Action- Reaction Forces) Action- reaction forces propel the swimmer through the water. The swimmer pushes against the water and the water pushes the swimmer ahead.

Momentum Momentum is the product of an object’s mass and its velocity. Momentum= Mass X velocity Unit = kg*m/s

Practice Momentum Problems A 75 kg speed skater moving forward at 16m/s. A 135 kg ostrich running north at 16.2 m/s A 5.0 kg baby on a train moving eastward at 72m/s. A 0.8kg kitten running to the left at 6.5 m/s A 48.5kg passenger on a train stopped on the tracks.