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Monday 11-26 PS. Homework. Pg 858-859 Problems 111-113, 116-125 Due Wednesday. Conversions. Divide your gram (g) mass value by 1000 to determine the kilogram (kg) value Divide your speed in (km/hr) by 3.6 to get the speed in (m/s)
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Homework • Pg 858-859 • Problems 111-113, 116-125 • Due Wednesday
Conversions • Divide your gram (g) mass value by 1000 to determine the kilogram (kg) value • Divide your speed in (km/hr) by 3.6 to get the speed in (m/s) • (kJ) means kilojoules. Multiply the number of (kJ) by 1000 to get the value of energy in (j)
Write-up for Roller Coaster Project Discussion
General information • Write up section is due Tuesday • Neat, typed if at all possible • All answers must be completed in sentence form • Define the concepts asked in question, base your question on those definitions • Sketch may be on different paper, but have all measurements, velocity, GPE and KE information
Question #1 • What Simple machines can be connected to the construction or operation of your roller coaster?
Question #2, #3 • Produce a sketch (not a photocopy of some person’s sketch) • Indicate height values to every important point on the coaster (In meters) • Accurate line representing the track • IF your group filmed your coaster and you can e-mail the results, I will try to get it up on the web-site
Question #4 • Circle what was successfully completed on the 2 best runs on the track • Describe, in detail, the special section(s)
Question #5 • Get signatures from Me, if you have completed your runs • Add the date on which the runs were performed
Question #6 • Does the ball accelerate during the entire roller coaster run?
Question #7 • Indicate on your sketch, the point of greatest velocity of the ball during the run. • If you can’t decide between two label and explain both
Question #8 • Draw a free body diagram of the ball as it rolls down the first slope. • Arrows , direction • Label forces
Question #9 • Does the track exhibit any evidence of gaining elastic potential energy during the movement of the ball over it, during a run?
Question #10 • Indicate where does the ball has its most and least amount of GPE during its run on your sketch?
Question #11 • Indicate where the ball has its most and least amount of KE during its run on your sketch
Question #12 • Indicate the relationship between the amount of GPE and KE the ball has as it moves up a hill on the track
Question #13 • Does the ball possess the same amount of energy at the end of the run as it had in the beginning? • Forms of energy • Conservation of energy
Question #14 • If you make your hill too steep, the ball will fly off the top of it . Why does this occur • Inertia • Momentum • Newton’s laws
This is due Wednesday • Neat, typed if possible
Equations • GPE = mgh • KE = ½mv2 • a = (Vf – Vi)/t • p = mv • MA = fo / fi • W = f d • P = w / t
Question #15 • Calculate the GPE at start • What is the mass of your marble? small metal = 28.3 g clear glass = 8.5 g swirled glass = 6.0 g big metal = 67 g wood = 2.0 g What is acceleration due to gravity on Earth? What is the height?
Question #16 • Calculate the GPE at the bottom of the first hill
Question #17 • What is the difference in the amount of GPE in the problems 15 and 16?
Question #18 • If the all of the ball’s energy lost from GPE was converted into KE at the bottom of the first hill, what is the velocity of the ball?
Question #19 • What is the acceleration of the ball from the start to the bottom of the first hill, if it takes 5 seconds to travel between points • Initial velocity ? • Final velocity ?
Question #20 • What is the momentum of the ball at the bottom of the first hill?
Question #21 • What is the change in GPE of the ball from the start to finish of the roller coaster ride?
Question #22 • How much energy of the ball was lost due to friction and sound by the end of the roller coaster? • What else could take away some of the ball’s energy?
The rest of this week we will concentrate on the equations • Steps to solving a problem using an equation 1) Identify what is given 2) Identify what is wanted 3) Make sure all values are in correct units (kg, m, s , N, J, W) 4) Identify equation that relates the givens to what is wanted 5) Plug in givens 6) Solve for what you want
Question • A high jumper jumps 2.04 m. If the jumper has a mass of 67 kg, what is his gravitational potential energy at the highest point of the jump?
What is given? • 2.04 m • Height at highest point of jump • 67 kg • Mass of person
What is wanted? • What is his gravitational potential energy at the highest point of the jump? • GPE
What equation to use • Need to connect GPE with mass and height • GPE = mgh • G is the acceleration due to gravity • G is constant on earth’s surface = 9.8 or 10
Plug in and solve • GPE = m g h • GPE = (67) (10) (2.04) • Around 1300 J • The units are the units for energy, which can be used if all else is measured in m, kg, and s
Question #2 • A rock is rolling down a hill with a velocity of 4.67 m/s. It has the kinetic energy of 18.9 kJ. What is the mass of the rock?
Question • A team of horses is hitched to a cart. The team pulls with a force of 471 N. The cart travels 2.3 km in 20 minutes. Calculate the work done on the cart and the power delivered by the horses.
Scientific Notation • A method used to write very large or very small numbers in a more manageable way. • 15000 = 1.5 x 104
Write in scientific notation • The planet of Saturn has a mass of 568 500 000 000 000 000 000 000 000 kg In 1997, 70 294 601 planes either took off or landed at Chicago’s O’Hare airport