Presentation on theme: "Physical Science Unit 1 Motion. Mass Amount of matter in an object Units: kilogram (or gram) Measured: –Using a balance."— Presentation transcript:
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: m 3 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 10.0cm 3 sample of copper has a mass of 89.6g. What is the density of copper? 5. Silver has a density of 10.5 g/cm 3 and gold has a density of 19.3 g/cm 3. Which would have a greater mass, 5 cm 3 of silver or 5 cm 3 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.
Pressure –Result of a force distributed over an area Unit: Pa (pascal); N/m2 Temperature –Average amount of kinetic energy Factors that affect pressure –Temperature Raising temperature will increase the pressure (increase motion) –Volume- reducing volume increases pressure
Gas Laws Charles’s Law –Volume of a gas is directly proportional to its temperature If temperature increases, volume increases V 1 /T 1 = V 2 / T 2 Boyle’s Law –Volume of a gas is inversely proportional to its pressure If volume decreases pressure increases P 1 V 1 = P 2 V 2
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/s 2 An arrow can be used to represent strength and direction of force
Combining 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 1 st 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 2 nd 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/s 2 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/s 2 ) 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 3 rd 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.