AP PHYSICS MONDAY 15.01.26 STANDARDS: Agenda: 1.Warm Up 2.Collect all HW up to EAP#2 3.Potential...

AP PHYSICSMONDAY 15.01.26

STANDARDS:

Agenda:

1. Warm Up

2. Collect all HW up to EAP#2

3. Potential Energy Lab

HomeworkEAP #3

Warm UpA 20 kg ball rolling at 6 m/s collides with a stationary box and subsequently bounces backwards at 2m/s. How much work was done on the box? f3A describing forces with velocity,

acceleration, etc.

I –Independent Resilient IndividualsRST.11-12.9 Synthesize information from a range of sources into coherent understanding of a process, phenomenon, or concept,…

Learning Goal: SWBAT understand how potential energy is used up and converted to other forms of energy.

PERIOD 3

AP PHYSICSTUESDAY 15.01.27

STANDARDS:

Agenda:

1. Warm Up

2. Collect all HW up to EAP #3

3. Review Work Lab

4. #6 Conservation of Energy Lab

HomeworkEAP#4

Warm UpFind the change in potential energy of a 2000 kg elevator that moves from the 1st floor 1 meter above the ground to the 8th floor 25 meters above the ground. Is the work done by the elevator positive or negative?

f3A describing forces with velocity, acceleration, etc.


Learning Goal: SWBAT apply conservation of energy to a car rolling down a ramp.

AP PHYSICSWEDNESDAY 15.01.21

STANDARDS:

Agenda:

1. Warm Up

2. Review HW #4

3. Conservation of Energy Lab #6

HomeworkCATCH UP ON HW & Finish the Lab

Warm UpA 58kg person jumps 0.5 m into the air before sliding down a 3.5 m water slide. Right when the person is about to hit the water, how fast will s/he be moving if energy is conserved.



Learning Goal: SWBAT apply conservation of energy to a car rolling down a ramp.

AP PHYSICSTHURSDAY 15.01.29

STANDARDS:

Agenda:

1. Warm Up

2. AP FRQ Work Day HomeworkEAP # 5 EnergyCentripetal Motion & Gravity & Energy Quiz Monday (Multiple Choice)

Warm UpStudent A lifts a 50-N box from the floor straight up to a height of 40 cm in 2 s. Student B lifts a 40-N box straight up from the floor to a height of 50 cm in 1s.

Does B compared to Aa) do the same work but

develops more powerb) do the same work but

develops less powerc) do more work but develops

less powerd) do less work but develops

more power. Justify your answer.

5B5 energy can be transferred by an external for to do work on an object.


Learning Goal: SWBAT solve AP level problems relating to energy.

AP PHYSICSFRIDAY 15.01.30

STANDARDS:

Agenda:

1. Warm Up

2. Review Labs

3. Review EAP #6

4. MC Test Review

HomeworkReview for Test HW Due Monday

Warm UpA 0.5 kg car released from rest at the top of a smooth incline has gravitational energy of 6 J relative to the base of the incline. a. calculate the cart’s speed

at the bottom of the incline.

b. Calculate the gravitational potential energy ½ way down the incline.



Learning Goal: SWBAT review centripetal acceleration and energy for test.

#1 VERTICAL CIRCLE LAB

Using a timer, triple beam balance, a mass on a string, and a meter stick, experimentally find the Tension in the string at the top of the circle and at the bottom.

Hint: The following equations should help you determine which quantities you should measure, Fnet=ma, ac=v2/r, v=2πr/T . Free body diagrams and Free body diagram expressions, will make the process much easier also.

GRAVITATIONAL FORCE

F=Gm1m2/r2, Fc=mv2/r,

CAP #7

1. Deimos, a satellite of Mars, has an average radius of 6.3 km. If the gravitational force between Deimos and a 3.0 kg rock at its surface is 2.5x10-2N, what is the Mass of Deimos?

2. In 1874, a swarm of locusts descended on Nebraska. The swarm’s mass was estimated to be 25x109kg. If this swarm were split in half and the halves separated by 1.0x103 km, what would the magnitude of the gravitational force between the halves be?

3. Jupiter, the largest planet in the solar, system, has a mass 318 times that of Earth and a volume (4/3πr3) that is 1323 times greater than the Earth’s. Calculate the magnitude of the gravitational force exerted on a 50.0 kg mass on Jupiter’s surface. (look up the mass and radius of the earth online or in your books)

CAP#8 GRAVITATION FRQ

A student is given the set of orbital data for some of the moons of Saturn shown below and is asked to use the data to determine the mass MS of Saturn. Assume the orbits of these moons are circular.

a. Write an algebraic expression for the gravitational force between Saturn and one of its moons.

b. Use your expression from part (a) and the assumption of circular orbits to derive an equation for the orbital period T of a moon as a function of its orbital radius R.

c. Which quantities should be graphed to yield a straight line whose slope could be used to determine Saturn’s mass?

d. Complete the data table by calculating the two quantities to be graphed. Label the top of each column, including units.

e. Plot the graph on the axes below. Label the axes with the variables used and appropriate numbers to indicate the scale.

f. Using the graph, calculate a value for the mass of Saturn.

CAP#9

To study circular motion, two students use the hand-held device shown above, which consists of a rod on which a spring scale is attached. A polished glass tube attached at the top serves as a guide for a light cord attached the spring scale. A ball of mass 0.200 kg is attached to the other end of the cord. One student swings the teal around at constant speed in a horizontal circle with a radius of 0.500 m. Assume friction and air resistance are negligible.

a. Explain how the students, by using a timer and the information given above, can determine the speed of the ball as it is revolving.

b. The speed of the ball is determined to be 3.7 m/s. Assuming that the cord is horizontal as it swings, calculate the expected tension in the cord.

c. The actual tension in the cord as measured by the spring scale is 5.8 N. What is the percent difference between this measured value of the tension and the value calculated in part b.?

The students find that, despite their best efforts, they cannot swing the ball so that the cord remains exactly horizontal.

d. i. On the picture of the ball below, draw vectors to represent the forces acting on the ball and identify the force that each vector represents.

ii. Explain why it is not possible for the ball to swing so that the cord remains exactly horizontal.

iii. Calculate the angle that the cord makes with the horizontal.

EAP #1 WORK & POWER

1. Lake Point Tower in Chicago is the tallest apartment building in the United States. Suppose you take the elevator from the street level to the roof of the building. The elevator moves almost the entire distance at constant speed, so that it does 1.15x105J of work on you as it lifts the entire distance. If you mass is 60.0 kg, how tall is the building? If it takes 2 minutes, how much power does the elevator use.

2. During World War II, 16 huge wooden hangers were built for the United States Navy airships. The hangers were over 300 m long and had a maximum height of 52.0 m. Imagine a 40 kg block being lifted by a winch from the ground to the top of the hangar’s ceiling. If the winch does 2.08x104J of work in lifting the block, what force is exerted on the block? How much power is used by the winch if it takes 30 seconds ?

3. The longest shish kebab ever made was 881.0 m long. Suppose the meat and vegetables need to be delivered in a cart from one end of this shish kebab’s skewere to the other end. A cook pulls the cart by applying a force of 40.0 N at an angle of 45.00 degrees above the horizontal. If the force of friction acting on the cart is 28.00 N, what is the net work done on the cart and its contents during the delivery?

EAP #2 TRANSFER OF ENERGY

1. The tops of the towers of the Golden Gate Bridge, in San Francisco, are 227 m above the water. Suppose a worker drops a 655 g wrench from the top of a tower. If the average force of air resistance is 2.20 percent of the force of free fall, what will the kinetic energy of the wrench be when it hits the water?

2. Bonny Blair of the United States set a world record in speed skating when she skated 5.00x102 m with an average speed of 12.92 m/s. Suppose Blair crossed the finish line at this speed and then skated to a stop. If the work done by friction over a certain distance was -2830 J, what would Blair’s kinetic energy be, assuming her mass to be 55.0 kg.

3. The summit of Mount Everest is 8848.0 m above sea level, making it the highest summit on Earth. In 1953, Edmund Hillary was the first person to reach the summit. Suppose upon reaching there, Hillary slid a rock with a 45.0 g mass down the side of the mountain. If the rock’s speed is 27.0 m/s when it is 8806.0 m above sea level, how much work was done on the rock by air resistance?

4. In 1990, Roger Hickey of California reached a speed 35.0 m/s on his skateboard. Suppose it took 21 kJ of work for Roger to reach this speed from a speed of 25.0 m/s. Calculate Hickey’s mass.

A. From your Lab #3: Graph Force (y axis) vs. displacement (x axis). Create a best fit line. Answer: How would you use the graph to find Work or (ΔK) the change in kinetic energy? From your graph, find the change in kinetic energy.

EAP #3

1. Naim Suleimanoglu of Turkey has a mass of about 62 kg, yet he can lift nearly 3 times this mass. If the potential energy associated with a barbell lifted 1.70 m above the floor by Suleimanoglu is 3.04x103 J, what is the barbell’s mass?

2. Situated 4080 m above sea level, La Paz, Bolivia, is the highest capital in the world. If a car with a mass of 905 kg is driven from La Paz to a location that is 1860 m above sea level, what is the increase in potential energy?

3. In 1966 a special research cannon built in Arizona shot a projectile to a height of 180 km above the Earth’s surface. The potential energy associated with the projectile when its altitude was 10.0 percent of the maximum height was 1.48x107 J. What was the projectile’s mass? Assume that constant free-fall acceleration at this altitude is the same as at sea level.

#5 CONSERVATION OF ENERGY

Goal: To determine whether or not gravitational potential energy is conserved and converted into mechanical energy when it is released.

Experiment:

1. Determine the mass of your car (in kg) ___________

2. Set up a ramp using t4t materials and measure the height of the ramp (m) _____.

3. Calculate the potential energy at the top of the ramp.

4. What should be the speed of the car at the bottom of the ramp?

5. What is the actual speed at the bottom of the ramp?

6. Find % error.

7. Does this prove or disprove that energy is conserved? Justify your conclusion

8. Set up the ramp at 4 more heights and find the speed of the ball at each height.

9. Graph height (y) vs. velocity2 (x) and find the slope & equation of the line.

10. What do you think the slope means?

Equations: K=1/2 mv2, U=mgh, W=F * D, W=ΔU=ΔK, Ei=Ef

Don’t forget: Multiple trials = better data.

EAP #4

1. The largest watermelon ever grown had a mass of 118 kg. Suppose this watermelon were exhibited on a platform 5.00 m above the ground. After the exhibition, the watermelon is allowed to slide along to the ground along a smooth ramp. How high above the ground is the watermelon at the moment its kinetic energy is 4.61 kJ?

2. One species of eucalyptus tree, Eucalyptus regnens, grows to heights similar to those attained by California redwoods. Suppose a bird sitting on top of one specimen of eucalyptus tree drops a nut. If the speed of the falling nut at the moment it is 50.0 m above the ground is 42.7 m/s, how tall is the tree? Do you need to know the mass of the nut to solve this problem? Disregard air resistance.

3. In 1989, Michel Menin of France walked on a tightrope suspended under a balloon nearly at an altitude of 3150 m above the ground. Suppose a coin falls from Menin’s pocket during his walk. How high above the ground is the coin when its speed is 60.0 m/s?

EAP #5 CIRCULAR MOTION & ENERGY FRQ’S PG#1

A roller coaster ride at an amusement park lifts a car of mass 700 kg to point A at a height of 90 m above the lowest point on the track, as shown above. The car starts from rest at point A, rolls with negligible friction down the incline and follows the track around a loop of radius 20 m. Point B, the highest point on the loop, is at a height of 50 m above the lowest point on the track.

(a)i. Indicate on the figure the point P at which the maximum speed of the car is attained.

ii. Calculate the value vmsx of this maximum speed.

(b) Calculate the speed vB of the car at point B.

( c ) i. On the figure of the car below, draw and label vectors to represent the forces acting on the car when it is upside down at point B.

ii. Calculate the magnitude of all the forces identified in (c)

(d) Now suppose that friction is not negligible. How could the loop be modified to maintain the same speed at the top of the loop as found in (b)? Justify your answer.

EAP #5 PART 2A designer is working on a new roller coaster, and she begins by making a scale model.

On this model, a car of total mass 0.50 kg moves with negligible friction along the track shown in the figure above. The car is given an initial speed vo = 1.5 m/s at the top of the first hill of height 2.0 m. Point A is located at a height of 1.9 m at the top of the second hill, the upper part of which is a circular arc of radius 0.95 m.

(a) Calculate the speed of the car at point A.

(b) On the figure of the car below, draw and label vectors to represent the forces on the car at point A.

(c) Calculate the magnitude of the force of the track on the car at point A.

(d) In order to stop the car at point A, some friction must be introduced. Calculate the work that must be done by the friction force in order to stop the car at point A.

(e) Explain how to modify the track design to cause the car to lose contact with the track at point A before descending down the track. Justify your answer.

AP PHYSICS MONDAY 15.01.26 STANDARDS: Agenda: 1.Warm Up 2.Collect all HW up to EAP#2 3.Potential...

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