# Shared Flashcard Set

## Details

exam review
Exam review honors physics
50
Physics
01/07/2011

Term
 An object starts from rest and accelerates down an incline. If the object reaches a speed of 40m/s in 5s what is its average speed?
Definition
 x= 1/2(40)5=100m100m/5s= 20m/s
Term
 If a car is traveling at 50km/hr how long does it take to travel 40km?
Definition
 t=x/v therefore 0.80hr
Term
 Describe the shape of a position/time, velocity/time, and acceleration/time graph for an object starting from rest and accelerating in the positive direction.
Definition
 p/t= start from origin and gently curving upwardv/t= start from origin and straight line upwarda/t= flat horizontal line above x axis
Term
 A ball rolls down a 40 degree incline of height 10m. What distance does the ball go on the opposing incline of 30 degrees?
Definition
 20m=10m/sin30degrees
Term
 A ball rolls down a 40 degree incline of height 10m. How high does the ball go on the opposing incline of 30 degrees?
Definition
 10m conservation of energy says so, regardless of angle. It means it will go further but it will only reach a max of 10m
Term
 FInd kinetic energy of a 10kg object traveling at 10m/s
Definition
 1/2mv^2=500J
Term
 A rockfalls off a high cliff. How far has the rock fallen when its speed is 49m/s?
Definition
 v^2/2a= 49^2/2(9.8)= 122.5m
Term
 Find momentum of a 100kg cart moving with a speed of 7.5m/s.
Definition
 mv=100(7.5)=750kgm/s
Term
 If the direction of momentum is 40degrees the direction of velocity is?
Definition
 the same, 40 degrees, momentum is a vector
Term
 Identify scalar quantities.
Definition
 distance, speed, work, energy
Term
 Identify vector quantities.
Definition
 displacement, velocity, acceleration, force, momentum
Term
 The potential energy of a 5kg box at the top of a 30 degree incline 5m tall.
Definition
 mgh= 5(9.8)5=245J
Term
 The speed of a 5kg box at the bottom of a 30 degree incline 5m tall.
Definition
 mgh=1/2mv^29.8(5)=1/2v^29.9m/s
Term
 What does the slop on a position time graph tell you?
Definition
 velocity
Term
 What does the area under the curve on a velocity time graph tell you?
Definition
 Displacement
Term
 A 50kg object starting from rest slides down a frictionless incline with an acceleration of 3.5m/s^2. Find the total distance during the 4.0s.
Definition
 1/2 at^2=1/2(3.5)4^2=28m
Term
 A 50kg object starting from rest slides down a frictionless incline with an acceleration of 3.5m/s^2.Find the force to produce this acceleration.
Definition
 F=ma 50(3.5)=175N
Term
 A 50kg object starting from rest slides down a frictionless incline with an acceleration of 3.5m/s^2.What is the approximate weight of this object?
Definition
 F=mg 50(9.8)=490N
Term
 What is the speed of an object if the sum of the forces on it is zero?
Definition
 It is constant, whether it is zero or some quantitative value you will need more information. But it does not change from whatever it is .
Term
 [image]ID pts where there is a. stoppedb. constant velocityc. acceleration
Definition
 a. cdb. bc positive v, de negativec. ab positive accel
Term
 [image]IDpts where there isa. Find velocity at t=2sb. Find displacement between 2 and 5 s.
Definition
 a. 10m/s since curve is straight line same at all ptsb. Find area under curve = 105m
Term
 What is the total displacement of a student who walks 3 blocks east, 2 blocks north, 1 block west, and then 2 blocks south?
Definition
 2 blocks east
Term
 A motor having a maximum power rating of 8.1 x 104 watts is used to operate an elevator with a weight of 1.8 x 104 newtons. What is the maximum weight this motor can lift at an average speed of 3.0 meters per second?
Definition
 P=W/t = Fv81000W=F (3)F=27000NSince elevator in included in max weight, this is answer. If question asks for weight inside elevator then subtract 18000N (weight of elevator) from final answer.
Term
 [image]What is the spring constant for this spring?
Definition
 K=F/x watch axes carefully!20/.4= 50N/m
Term
 A spring has a spring constant of 120 newtons per meter. How much potential energy is stored in the spring as it is stretched 0.20 meter?
Definition
 1/2kx^2=EPE1/2(120).2^2= 2.4J
Term
 How much work is done on a downhill skier by an average braking force of 9.8 x 102 newtons to stop her in a distance of 10. meters?
Definition
 W= Change in KE=Fd980(10)=9800J
Term
 [image]If the carts are initially at rest, what is the approximate speed of cart B after the spring is released?
Definition
 Conservation of momentum0=mv1 + mv23(.33)=5(v)v= .198m/s
Term
 A pool ball leaves a 0.60-meter high table with an initial horizontal velocity of 2.4 m/s. Predict the time required for the pool ball to fall to the ground and the horizontal distance between the table's edge and the ball's landing location.
Definition
 -0.60 m = (0 m/s)•t + 0.5•(-9.8 m/s/s)•t2t = 0.350 sx = (2.4 m/s)•(0.3499 s)x = 0.84 m
Term
 A football is kicked with an initial velocity of 25 m/s at an angle of 45-degrees with the horizontal. Determine the time of flight, the horizontal distance, and the peak height of the football.
Definition
 Range=63.8mTime= 3.6sPeak Height= vt + 1/2at^2= 17.7(1.8)+ -1/2(9.8)1.8^2= 16m
Term
 Galileo is often credited with the early discovery of four of Jupiter's many moons. The moons orbiting Jupiter follow the same laws of motion as the planets orbiting the sun. One of the moons is called Io - its distance from Jupiter's center is 4.2 units and it orbits Jupiter in 1.8 Earth-days. Another moon is called Ganymede; it is 10.7 units from Jupiter's center. Make a prediction of the period of Ganymede using Kepler's law of harmonies.
Definition
 Answer: T = 7.32 daysGiven:Io: Rio = 4.2 and Tio = 1.8Ganymede: Rg = 10.7 Tg=???Use Kepler's 3rd law to solve.(Tio)^2/(Rio)3 = 0.04373;so (Tg)^2 / (Rg)3 = 0.04373Proper algebra would yield (Tg)^2 = 0.04373 • (Rg)3(Tg)2 = 53.57 so Tg = SQRT(53.57) = 7.32 days
Term
 Kepler's three laws of planetary motion
Definition
 * The path of the planets about the sun is elliptical in shape, with the center of the sun being located at one focus. (The Law of Ellipses) * An imaginary line drawn from the center of the sun to the center of the planet will sweep out equal areas in equal intervals of time. (The Law of Equal Areas) * The ratio of the squares of the periods of any two planets is equal to the ratio of the cubes of their average distances from the sun. (The Law of ratios)
Term
 The fact that satellites can maintain their motion and their distance above the Earth is fascinating to many. How can it be? What keeps a satellite up?
Definition
 Its tangential velocity is great enough in tandem with gravity which changes its direction.
Term
 A satellite is orbiting the earth. Which of the following variables will affect the speed of the satellite? a. mass of the satellite b. height above the earth's surface c. mass of the earth
Definition
 B. Must add radius of earth to this total rc. Mass of central body only
Term
 Astronauts on the orbiting space station are weightless because... a. there is no gravity in space and they do not weigh anything. b. space is a vacuum and there is no gravity in a vacuum. c. space is a vacuum and there is no air resistance in a vacuum. d. the astronauts are far from Earth's surface at a location where gravitation has a minimal affect.
Definition
 Since the force of gravity cannot be felt without any other opposing forces, you would have no sensation of it. You would feel weightless when in a state of free fall.
Term
 Otis L. Evaderz is conducting his famous elevator experiments. Otis stands on a bathroom scale and reads the scale while ascending and descending the John Hancock building. Otis' mass is 80 kg. He notices that the scale readings depend on what the elevator is doing. Use a free-body diagram and Newton's second law of motion to solve the following problems.a. What is the scale reading when Otis accelerates upward at 0.40 m/s2?
Definition
 Add 0.4 to 9.8 then multiply by mass.10.2(80)=816N
Term
 Which of the following will cause the current through an electrical circuit to decrease? Choose all that apply. a. decrease the voltage b. decrease the resistance c. increase the voltage d. increase the resistance
Definition
 Answers: A and DThe current in a circuit is directly proportional to the electric potential difference impressed across the circuit and inversely proportional to the resistance of the circuit. Reducing the current can be done by reducing the voltage (choice A) or by increasing the resistance (choice D).
Term
 If the resistance of a circuit were tripled, then the current through the circuit would be ____. a. one-third as much b. three times as much c. unchanged d. ... nonsense! There would be no way to make such a prediction.
Definition
 Answer: ACurrent is inversely proportional to the resistance. A threefold increase in the resistance would cause a threefold decrease in the current.
Term
 [image]Use the Ohm's law equation to determine the missing values in the following circuits.
Definition
 [image]
Term
 As the number of resistors in a series circuit increases, the overall resistance __________ (increases, decreases, remains the same) and the current in the circuit __________ (increases, decreases, remains the same).
Definition
 As the number of resistors in a series circuit increases, the overall resistance increases and the current in the circuit decreases.
Term
 [image]Three resistors are connected in series. If placed in a circuit with a 12-volt power supply. Determine the equivalent resistance, the total circuit current, and the voltage drop across and current at each resistor.
Definition
 [image]
Term
 [image]Three resistors are connected in parallel. If placed in a circuit with a 12-volt power supply. Determine the equivalent resistance, the total circuit current, and the voltage drop across and current in each resistor.
Definition
 [image]
Term
 A pendulum bob is pulled back to position A and released from rest. The bob swings through its usual circular arc, the bottom of the swing is position B and is caught at position C, the highest point on the opposite side. Determine the position (A, B, C or all the same) where the … a. … force of gravity is the greatest? b. … restoring force is the greatest? c. … speed is the greatest? d. … potential energy is the greatest? e. … kinetic energy is the greatest f. … total mechanical energy is the greatest?
Definition
 a. The force of gravity is everywhere the same since it is not dependent upon the pendulum's position; it is always the product of mass and 9.8 N/kg.b. The restoring force is greatest at A and C; the further that the bob is from the rest position, the greater the restoring force.c. The speed is greatest at B. The restoring force accelerates the bob from position A to position B. By the time the bob reaches B, it has accelerated to its maximum speed.d. The potential energy is the greatest at A and C. The potential energy is the greatest at the highest position.e. The kinetic energy is the greatest at position B; kinetic energy is greatest at the lowest position. By the time the bob reaches B, all the original potential energy has been transformed into kinetic energy.f. The total mechanical energy is everywhere the same since energy is conserved by a pendulum.
Term
 A force of 16 N is required to stretch a spring a distance of 40 cm from its rest position. What force (in Newtons) is required to stretch the same spring … a. … twice the distance? b. … three times the distance? c. … one-half the distance?
Definition
 As the extension, so the force. Force and stretch are proportional to one another such that if you double the force, the amount of stretch will double. If you triple the force, the amount of stretch will triple. If you half the force, the amount of stretch will halve. So the answers here are:a. 32 N (twice the stretch requires twice the force)b. 48 N (three times the stretch requires three times the force)c. 8 N (one-half the stretch requires one-half the force)
Term
 A transverse wave is transporting energy from east to west. The particles of the medium will move_____.
Definition
 The particles would be moving back and forth in a direction perpendicular to energy transport. The waves are moving westward, so the particles move northward and southward.
Term
 [image]Find wavelength and amplitude. Find period if this image was completed in 6.0s.
Definition
 Wavelength=AAmplitude=DPeriod of one wave= 6/3.5 = 1.71sFrequency=1/T= .584Hz
Term
 [image]6. The reflected pulse in medium 2 ________ (will, will not) be inverted because _____________.7. The speed of the transmitted pulse will be ___________ (greater than, less than, the same as) the speed of the incident pulse.8. The speed of the reflected pulse will be ______________ (greater than, less than, the same as) the speed of the incident pulse.9. The wavelength of the transmitted pulse will be ___________ (greater than, less than, the same as) the wavelength of the incident pulse.10. The frequency of the transmitted pulse will be ___________ (greater than, less than, the same as) the frequency of the incident pulse.
Definition
 6. will... because the reflection occurs for a wave in a less dense medium heading towards a more dense medium.7. less than8. the same as9. less than10. the same as
Term
 A large truck and a Volkswagen have a head-on collision. a. Which vehicle experiences the greatest force of impact? b. Which vehicle experiences the greatest impulse? c. Which vehicle experiences the greatest momentum change? d. Which vehicle experiences the greatest acceleration?
Definition
 a, b, c: the same for each.Both the Volkswagon and the large truck encounter the same force, the same impulse, and the same momentum change (for reasons discussed in this lesson).d: Acceleration is greatest for the Volkswagon. While the two vehicles experience the same force, the acceleration is greatest for the Volkswagon due to its smaller mass. If you find this hard to believe, then be sure to read the next question and its accompanying explanation.
Term
 In a physics lab, 0.500-kg cart (Cart A) moving rightward with a speed of 92.8 cm/s collides with a 1.50-kg cart (Cart B) moving leftward with a speed of 21.6 cm/s. The two carts stick together and move as a single object after the collision. Determine the post-collision speed of the two carts.
Definition
 mv1i +mv2i = (m1 +m2)vf.5(92.8)+ 1.5(-21.6)= (.5 +1.5)vfvf=7.0cm/s
Term
 Two ice dancers are at rest on the ice, facing each other with their hands together. They push off on each other in order to set each other in motion. The subsequent momentum change (magnitude only) of the two skaters will be ____. a. greatest for the skater who is pushed upon with the greatest force b. greatest for the skater who pushes with the greatest force c. the same for each skater d. greatest for the skater with the most mass e. greatest for the skater with the least mass
Definition
 Answer: CIn this situation, the force on the first ice dancer is the same as the force on the second ice dancer (Newton's third law of motion). And these forces act for the same amount of time to cause equal impulses on each skater. Since impulse is equal to momentum change, both skaters must also have equal momentum changes. The mass of the individual skaters will only effect the subsequent velocity change.
Term
 A 1.5-kg cannon is mounted on top of a 2.0-kg cart and loaded with a 52.7-gram ball. The cannon, cart, and ball are moving forward with a speed of 1.27 m/s. The cannon is ignited and launches a 52.7-gram ball forward with a speed of 75 m/s. Determine the post-explosion velocity of the cannon and cart.
Definition
 Answer: 0.160 m/s (rounded) MomentumBefore Explosion MomentumAfter ExplosionCart & Cannon (3.5 kg) • (1.27 m/s)= 4.445 kg•m/s (3.5 kg) • vTennis Ball (0.0527 kg) • (1.27 m/s)= 0.06693 kg•m/s (0.0527 kg) • (75 m/s)= 3.9525 kg•m/sTotal 4.5119 kg•m/s 4.5119 kg•m/s4.445 kg•m/s + 0.06693 kg•m/s = (3.5 kg) • v + 3.9525 kg•m/s4.445 kg•m/s + 0.06693 kg•m/s - 3.9525 kg•m/s = (3.5 kg) • v0.5594 kg •m/s = (3.5 kg) • v(0.5594 kg •m/s) / (3.5 kg) = v0.1598 m/s = v
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