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August 1, 2014

Homework Help: Science: Physics

Recent Homework Questions About Physics

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Physics
While playing a game of billiards, your 0.50 kg cue ball, travelling at 1.9 m/s, glances off a stationary 0.30 kg billiard ball so that the billiard ball moves off at 1.3 m/s at an angle of 32º clockwise from the cue ball’s original path. What is the final speed of ...
Sunday, June 23, 2013 at 3:01am

physics
A coin is at the bottom of a fountain 60 cm deep. The water in the fountain is frozen. What is the apparent depth of the coin? The index of refraction of ice is 1.31.
Sunday, June 23, 2013 at 2:18am

Physics
What is the factor of safety of a steel hanger having an ultimate strength of 550.000MPa and supporting a load of 64000.000N. The steel hanger in question has a cross sectional area of 7.600cm^2 ANS= Round to 3 decimal places Safety factor = design load/ load = 550.000MPa = ...
Saturday, June 22, 2013 at 3:48pm

Physics
A block of mass m1 is on top of a block of mass m2. Block 2 is connected by an ideal rope passing through a pulley to a block of unknown mass m3 as shown. The pulley is massless and frictionless. There is friction between block 1 and 2 and between the horizontal surface and ...
Saturday, June 22, 2013 at 2:41pm

physics
Two construction workers each of mass m raise themselves on a hanging platform using pulleys as shown above. If the platform has a mass of 0.5m, the initial distance between the pulleys and the platform is d, and the workers each pull with a force f on the ropes, what is the ...
Saturday, June 22, 2013 at 2:41pm

physics
A 2.0-m-tall, 30-cm-diameter concrete column supports a 3.0×105kg load. By how much is the column compressed (in mm) ?
Saturday, June 22, 2013 at 2:34pm

Physics
A seesaw is 4 meters long and is pivoted in the middle. There is a 350 N child on the left end. Where will a 540 N person have to sit to balance the seesaw?
Saturday, June 22, 2013 at 1:45pm

Physics
A cook puts 7.20 g of water in a 2.00-L pressure cooker that is then warmed to 530°C. What is the pressure inside the container? (Assume room temperature is 20°C.)
Saturday, June 22, 2013 at 12:21pm

Physics
A 2.60-mol sample of oxygen gas is confined to a 5.03-L vessel at a pressure of 7.95 atm. Find the average translational kinetic energy of the oxygen molecules under these conditions.
Saturday, June 22, 2013 at 12:20pm

Physics
What is the factor of safety of a steel hanger having an ultimate strength of 550.000MPa and supporting a load of 64000.000N. The steel hanger in question has a cross sectional area of 7.600cm^2 ANS= Round to 3 decimal places Safety factor = design load/ load = 550.000MPa = ...
Saturday, June 22, 2013 at 12:11pm

Physics
A tie bar is made of a material having a tensile strength of 231MPa and has to carry a load of 225kN. What is the diameter of the bar if a factor of safety of 7 is applied? Where do I begin?
Saturday, June 22, 2013 at 12:03pm

physics
Noah wants to swim across a river 10 m wide, flowing from north to south. He swims so his velocity with respect to the river is 2 m/s due east, and the river moves at 4 m/s. How far downstream in m from his starting point will he reach the other side?
Saturday, June 22, 2013 at 5:13am

physics
Noah wants to swim across a river 10 m wide, flowing from north to south. He swims so his velocity with respect to the river is 2 m/s due east, and the river moves at 4 m/s. How far downstream in m from his starting point will he reach the other side?
Saturday, June 22, 2013 at 5:05am

physics
Optical fibers are devices used for guiding light in many applications, most notably for fast communication. A fiber consists of a glass cylinder surrounded by a wall covered in a special coating. The fibers work on a principle called total internal reflection: light enters ...
Saturday, June 22, 2013 at 2:16am

Physics
A 2.0X10^4 N car is stopped on a 30 degree hill. If friction is negligible, what is the force of the car pushing into the hill?
Friday, June 21, 2013 at 11:52pm

Physics
In order to stop a Ferris wheel, a force is applied that accelerates at a rate of -0.010rad/s^2. How long will it take the Ferris wheel to stop?
Friday, June 21, 2013 at 11:49pm

physics
a tennis ball was held 4.5 ft above the surface of a tennis court and was thrown vertically downward with an initial velocity whose magnitude was 12 fps. Determine the magnitude of the velocity of the ball just before it struck the surface of the court
Friday, June 21, 2013 at 11:44pm

physics
an airplane was moving with a velocity equal to 150 mph when the velocity was increased with uniform acceleration to 300 mph in 5 min. Calculate the number of miles the airplane traveled during that interval
Friday, June 21, 2013 at 11:40pm

Physics
A rope exerts a constant horizontal force of 203N pulling a 68-kg crate across the floor. The velocity of the crate is observed to increase from 3m/s to 5m/s in a time of 4 seconds under the influence of this force and the frictional force exerted by the floor on the crate. ...
Friday, June 21, 2013 at 7:31pm

Physics
A rope exerts a constant horizontal force of 203N pulling a 68-kg crate across the floor. The velocity of the crate is observed to increase from 3m/s to 5m/s in a time of 4 seconds under the influence of this force and the frictional force exerted by the floor on the crate.
Friday, June 21, 2013 at 7:30pm

Physics
What is the factor of safety of a steel hanger having an ultimate strength of 550.000MPa and supporting a load of 64000.000N. ANS= Round to 3 decimal places Where do I begin?
Friday, June 21, 2013 at 7:21pm

Physics
A tie bar is made of a material having a tensile strength of 231MPa and has to carry a load of 225kN. What is the diameter of the bar if a factor of safety of 7 is applied? Where do I begin?
Friday, June 21, 2013 at 7:09pm

Physics
If a plane is flying 40 mph with a tailwind of 6 mph, how fast is the plane going.
Friday, June 21, 2013 at 4:15pm

physics
a skaterboarder is moving 5.25 m/s when he starts to roll up a frictionless hill. how much higher is he when he comes to a stop? (energy problem)
Friday, June 21, 2013 at 12:24pm

physics
a skaterboarder is moving 5.25 m/s when he starts to roll up a frictionless hill. how much higher is he when he comes to a stop? (energy problem)
Friday, June 21, 2013 at 12:23pm

science (physics)
a skaterboarder is moving 5.25 m/s when he starts to roll up a frictionless hill. how much higher is he when he comes to a stop? (energy problem)
Friday, June 21, 2013 at 12:22pm

physics
a watermelon has a mass of 8kg and 600 g . how mich force of gravity of the earthwill it experience ?what will be its weight on the earth and the moo
Friday, June 21, 2013 at 10:04am

Physics
we have a test coming up and I cannot figure out the practice question. Can somebody please help? Aaron throws a 7.5 kg bowling ball by applying a 45 N force for a time of 0.90seconds. What is the impulse Aaron applies to the ball? What is the ball's speed at the end of ...
Friday, June 21, 2013 at 8:21am

physics
Often in physics we won't be able to predict motion of a bunch of objects exactly and so we resort to statistical methods. An example of a statistical approach is the resulting profile of a bunch of disks dropped through a series of pegs. As each disk falls it encounters ...
Friday, June 21, 2013 at 1:41am

Physics
(delta)Eg = -14.7J Therefore, Ek = -(delta)Eg = 14.7J I don't understand how you'd come to the above conclusion? Does Ek just always equal -(delta)Eg?
Friday, June 21, 2013 at 12:15am

Physics
A q = +3.00 mC test charge is placed inside a constant uniform electric field created in a parallel plate capacitor connected to a battery of unknown voltage.   The capacitor is made of two parallel plates each with area equal to 0.250 m2 separated by a distance of 0....
Thursday, June 20, 2013 at 10:00pm

Physics
A capacitor is constructed from two conducting with a plate separation of d. The voltage between the plates is 31.2 volts and the electric field between the two plates is measured to be E = 2805 V/m. What is the minimum amount of force needed to push an electron from the ...
Thursday, June 20, 2013 at 9:58pm

Physics
A charge q=+5.11 mC (millicoulombs) has a mass of 0.00456 kg and is accelerated by two rings connected to a voltage source of 1378 volts. What is the velocity of the charge when it passes through the second ring?
Thursday, June 20, 2013 at 9:57pm

Physics
Three uniform spheres of masses m1 = 3.50 kg, m2 = 4.00 kg, and m3 = 6.50 kg are placed at the corners of a right triangle (see figure below). Calculate the resultant gravitational force on the object of mass m2, assuming the spheres are isolated from the rest of the Universe...
Thursday, June 20, 2013 at 5:41pm

physics
A train travel some distance with a speed of 30km/hr and return with a speed of 45km/hr. Calculate average speed.
Thursday, June 20, 2013 at 3:05am

physics
A train travel some distance with a speed of 30km/hr and return with a speed of 45km/hr. Calculate average speed.
Thursday, June 20, 2013 at 3:05am

physics
A train travel some distance with a speed of 30km/hr and return with a speed of 45km/hr. Calculate average speed.
Thursday, June 20, 2013 at 3:05am

physics
A train travel some distance with a speed of 30km/hr and return with a speed of 45km/hr. Calculate average speed.
Thursday, June 20, 2013 at 3:05am

physics
Explain why it would not make sense to use a full-size glass thermometer to measure the temperature of a thimbleful of hot water?
Wednesday, June 19, 2013 at 10:02pm

Physics (trig)
The height of an outdoor basketball backboard is 12 1/3 feet and the backboard casts a shadow 19 1/5 feet. Find the angle of elevation of the sun (answer in units of degrees). Can someone help me with the formula? Thank you!
Wednesday, June 19, 2013 at 9:10pm

Physics (Intro)
Initially, a spring-mass system completes 20.0 vibrations in 5.0 seconds, with a 2.0 cm amplitude. The same mass is pulled 5.0 cm away from the equilibrium position, then released. What will the frequency be?
Wednesday, June 19, 2013 at 8:26pm

physics
A parallel-plate capacitor is formed from two 1.0{\rm cm} \times 1.0{\rm cm} electrodes spaced 2.8{\rm mm} apart. The electric field strength inside the capacitor is 1.0\times10^{6}{N/C}} part a What is the charge (in {\rm nC}) on positive electrode? part b What is the charge...
Wednesday, June 19, 2013 at 6:25pm

Physics tough
If approximately 70% of the Earth's surface is covered with water, what is the order of magnitude for the number of raindrops in the world's oceans? Hint: The order of magnitude of 2478=2.478×10^3 is 3.
Wednesday, June 19, 2013 at 2:19am

physics
Every few hundred years most of the planets line up on the same side of the Sun
Wednesday, June 19, 2013 at 12:17am

Physics
A planet has a mass of 6.22 × 1023 kg and a radius of 2.51 × 106 m. (a) What is the acceleration due to gravity on this planet? (b) How much would a 77.7-kg person weigh on this planet?
Tuesday, June 18, 2013 at 11:21pm

physics
A 4.3 g mass is released from rest at C which has a height of 0.8 m above the base of a loop-the-loop and a radius of 0.31 m. The acceleration of gravity is 9.8 m/s2 . Find the normal force pressing on the track at A, where A is at the same level as the center
Tuesday, June 18, 2013 at 10:20pm

physics
A woman on a bridge 81.6 m high sees a raft floating at a constant speed on the river below. She drops a stone from rest in an attempt to hit the raft. The stone is released when the raft has 9.13 m more to travel before passing under the bridge. The stone hits the water 4.30 ...
Tuesday, June 18, 2013 at 9:52pm

Physics
A golf ball rolls off a horizontal cliff with an initial speed of 12.2 m/s. The ball falls a vertical distance of 17.3 m into a lake below. (a) How much time does the ball spend in the air? (b) What is the speed v of the ball just before it strikes the water?
Tuesday, June 18, 2013 at 9:44pm

Physics
A meteoroid is speeding through the atmosphere, traveling east at 23.1 km/s while descending at 18.3 km/s. What is its speed, in km/s?
Tuesday, June 18, 2013 at 9:43pm

Physics
In a football game a kicker attempts a field goal. The ball remains in contact with the kicker's foot for 0.0475 s, during which time it experiences an acceleration of 417 m/s2. The ball is launched at an angle of 59.7° above the ground. Determine the (a) horizontal ...
Tuesday, June 18, 2013 at 9:43pm

Physics
A tennis ball is struck and departs from the racket horizontally with a speed of 27.3 m/s. The ball hits the court at a horizontal distance of 18.7 from the racket. How far above the court is the tennis ball when it leaves the racket?
Tuesday, June 18, 2013 at 9:43pm

Physics/Mechanics
We will obtain bending moment diagrams for three beams and calculate stresses inside the beams. For each beam, take the x-axis along the neutral axis of the beam, oriented from left to right, with origin at A. HW7_1A_1 : 5.0 POINTS For the beam above, obtain symbolic ...
Tuesday, June 18, 2013 at 9:24pm

Physics
Calculate the change in potential energy of a 86.9 kg man when he takes an elevator from the first floor to 15th floor, if the distance between floors is 4.47 m. *This building has a thirteenth floor! Keep in mind that he stands on the floor of the top floor, not its ceiling!
Tuesday, June 18, 2013 at 9:21pm

physics
Suppose a car is traveling at +20.7 m/s, and the driver sees a traffic light turn red. After 0.314 s has elapsed (the reaction time), the driver applies the brakes, and the car decelerates at 5.00 m/s2. What is the stopping distance of the car, as measured from the point where...
Tuesday, June 18, 2013 at 9:14pm

Physics
A mass M is initially at rest on a horizontal surface, μs=0.30 and μk=0.20 . A horizontal string then pulls M with a tension T. N is the normal component of the contact force. All quantities below are magnitudes. Answers are either true or false. 1)The total force on...
Tuesday, June 18, 2013 at 8:42pm

Physics
Two blocks with masses M1=8.50kg and M2=1.40kg are attached by a thin string which goes over a frictionless, massless pulley. M1 slides on an incline and there is friction between M1 and the incline. The incline is at an angle of 23.0 degrees from horizontal. M2 travels down ...
Tuesday, June 18, 2013 at 8:40pm

physics
A 13 g bullet is stopped in a block of wood ( m w = 3 . 1 kg). The speed of the bullet- plus-wood combination immediately after the collision is 0 . 57 m / s. What was the original speed of the bullet? Answer in units of m / s
Tuesday, June 18, 2013 at 6:50pm

physics
please give me some idea for making a working model based on optics. Like combination of light and lenses, spectrum etc......& how can i make a working model with the use of contact lenses....
Tuesday, June 18, 2013 at 4:58pm

Physics
A football is punted at an angle of 44.6 with the horizontal. if it stays in the air for 3.6 seconds, what was the initial velocity of the football?
Tuesday, June 18, 2013 at 4:10pm

Physics (algebra)
the sonar of a navy cruiser detects a submarine that is d=4601 ft from the cruiser. the angle between the water level and the submarine is 0=32 degrees. What formula should I use to solve?
Tuesday, June 18, 2013 at 3:34pm

Physics
Two forces F1 = -7.50i + 6.00j and F2 = 8.40i + 7.50j are acting on a mass of m = 6.20 kg. The forces are measured in newtons. What is the magnitude of the object's acceleration? Can you show me step by step? I'm trying to study for an exam.
Tuesday, June 18, 2013 at 3:14pm

physics
Two 4.3 kg physical science textbooks on a bookshelf are 0.25 m apart. What is the magnitude of the gravitational attraction between the books
Tuesday, June 18, 2013 at 3:12pm

urgent physics..
Adventurous Mary tries a new game: she puts on her rollerblades and throws the ball towards the wall, lets it bounce off, catches it again, throws it right back, and so on. She notices a strange thing: after the second throw, she is unable to catch the ball anymore since the ...
Tuesday, June 18, 2013 at 2:32pm

physics
A police car is traveling at a velocity of 15.0 m/s due north, when a car zooms by at a constant velocity of 44.0 m/s due north. After a reaction time 0.700 s the policeman begins to pursue the speeder with an acceleration of 5.00 m/s^2. Including the reaction time, how long ...
Tuesday, June 18, 2013 at 12:31pm

physics
A cement block accidentally falls from rest from the ledge of a 51.5 -m-high building. When the block is 12.9 m above the ground, a man, 1.60 m tall, looks up and notices that the block is directly above him. How much time, at most, does the man have to get out of the way?
Tuesday, June 18, 2013 at 12:11pm

Physics
Optical fibers are devices used for guiding light in many applications, most notably for fast communication. A fiber consists of a glass cylinder surrounded by a wall covered in a special coating. The fibers work on a principle called total internal reflection: light enters ...
Tuesday, June 18, 2013 at 11:36am

physics
If I have 1.5 moles of an ideal gas at a pressure of 3 atmospheres and a volume of 7 liters, what is the temperature?
Tuesday, June 18, 2013 at 11:19am

physics
a polar satellite is launched at 850 km above Earth .find its orbital speed.
Tuesday, June 18, 2013 at 11:18am

Physics
A thin massless horizontal pipe rotates about a vertical axis with angular speed ω as shown in the figure. A small bug, located at a distance r from the axis, starts crawling inside the pipe at constant speed v (relative to the pipe). Because of the bug, the motor must ...
Tuesday, June 18, 2013 at 11:07am

Physics
The latent heat of fusion of alcohol is 50 kcal/kg and its melting point is -54oC. It has a specific heat of 0.60 in its liquid state. Calculate the energy needed to melt 2.0 kg of solid alcohol at -54o and raise it to a temperature of -4°C.
Tuesday, June 18, 2013 at 9:35am

Physics
A pulley system lifts a 500-lb block 1.0 foot with an effort of only 50 lb. If the 50 lb moves 30 feet, calculate the efficiency of the pulley system.
Tuesday, June 18, 2013 at 9:32am

Physics
A uniform meterstick pivoted at its center has a 80.0 mass suspended at the 27.0 position. At what position should a 85.0 mass be suspended to put the system in equilibrium? What mass would have to be suspended at the 90.0 position for the system to be in equilibrium?
Tuesday, June 18, 2013 at 9:27am

Physics
Calculate the total energy of 4.0 kg object moving horizontally at 20 m/s 50 meters above the surface. Please help me!!!!!
Tuesday, June 18, 2013 at 9:23am

Physics
A rope goes over a circular pulley with a radius of 5.5 If the pulley makes 6 revolutions without the rope slipping, what length of rope passes over the pulley?
Tuesday, June 18, 2013 at 9:16am

Physics
A cylinder with a diameter of 16 rolls with an angular speed of 0.055 on a level surface. If the cylinder experiences a uniform tangential acceleration of 0.020 without slipping until its angular speed is 1.0 , through how many complete revolutions does the cylinder rotate ...
Tuesday, June 18, 2013 at 9:13am

physics
This qusetion was about a journey between two towns. During the start of the journey the odometer reads 39593 ( the reverse of the no is also the same) and at the end of the journey again the odometer reads a number similar to prior one....If the max speed is 90km/hr during ...
Tuesday, June 18, 2013 at 8:27am

physics
If a dog whistle has a frequency of 30000 hertz. What is the wavelength of the sound emitted (Approximate speed of sound is 340 m/s)
Tuesday, June 18, 2013 at 2:28am

physics
Adventurous Mary tries a new game: she puts on her rollerblades and throws the ball towards the wall, lets it bounce off, catches it again, throws it right back, and so on. She notices a strange thing: after the second throw, she is unable to catch the ball anymore since the ...
Tuesday, June 18, 2013 at 1:55am

physics
In a synchrotron, electrons are accelerated to speeds close to the speed of light v≈c≈3×108 m/s Suppose that in a synchrotron, 100 billion (1011) electrons move in a circular orbit of circumference L=300 m . Determine the electric current in Amps due the flow...
Tuesday, June 18, 2013 at 1:55am

physics
A ball is thrown upward with an initial velocity of 14 m/s. At what time does the ball reach the high point in its flight? (Use the approximate value of g = 10 m/s2 and remember that the velocity is equal to zero at the high point.)
Monday, June 17, 2013 at 10:20pm

Physics
Can anyone help with which formula I should use to solve this: During a head on car crash, the car is designed to slow down as its front end crumples. If a person can survive an acceleration of -33 m/s how far must the front end crumple if the car was initially traveling at 28...
Monday, June 17, 2013 at 7:57pm

physics
orange light (lambda=630nm) hits diffraction grating which has a line spacing of (mu)m. The interference pattern is seen on a screen that is 4.0m away. what is the distance between the central bright spot and the first order bright spot on the screen. (sorry I don't have ...
Monday, June 17, 2013 at 6:32pm

Physics
How far do you travel if you start at 5.6 m/s and slow down at 2.5 m/s until you stop?
Monday, June 17, 2013 at 5:57pm

Physics
A herd of wildebeests led by Roger is charging down the hall on the way to lunch. They start out at 10 m/s and accelerate at a constant rate for 5.35 s to reach 34 m/s by the time they reach the stairs. How quickly did Roger's velocity change?
Monday, June 17, 2013 at 5:55pm

Physics
During a head on car crash, the car is designed to slow down as its front end crumples. If a person can survive an acceleration of -33 m/s how far must the front end crumple if the car was initially traveling at 28 m/s?
Monday, June 17, 2013 at 5:52pm

science physics
A chicken decides to cross a road. The road is perfectly straight, runs north-south, and is full of cars driving by from south to north. The cars have a log-normal distribution for the distance between each car. However, the cars all travel at 80 km/hr. The chicken stands next...
Monday, June 17, 2013 at 5:24pm

Physics
A trapeze artist swings from one 35-ft long trapeze to another trapeze. She releases one trapeze at a 30 degree angle relative to the vertical. She flies through the air, catching the other trapeze 18 ft away at the same elevation. What was her release velocity?
Monday, June 17, 2013 at 3:43pm

Physics
A 747 jetliner lands and begins to slow to a stop as it moves along the runway. If its mass is 3.42×105 , its speed is 28.0 , and the net braking force is , what is its speed 8.27 later?
Monday, June 17, 2013 at 3:36pm

physics
What is the electric field intensity produced by a charge at 10 meters, where the electric potential is 1.44 volts?
Monday, June 17, 2013 at 3:12pm

physics
A cement block accidentally falls from rest from the ledge of a 51.5 -m-high building. When the block is 12.9 m above the ground, a man, 1.60 m tall, looks up and notices that the block is directly above him. How much time, at most, does the man have to get out of the way?
Monday, June 17, 2013 at 12:50pm

physics
A pellet gun is fired straight downward from the edge of a cliff that is 27.1 m above the ground. The pellet strikes the ground with a speed of 25.9 m/s. How far above the cliff edge would the pellet have gone had the gun been fired straight upward?
Monday, June 17, 2013 at 12:41pm

physics
A hot-air balloon is rising upward with a constant speed of 2.00 m/s. When the balloon is 3.37 m above the ground, the balloonist accidentally drops a compass over the side of the balloon. How much time elapses before the compass hits the ground?
Monday, June 17, 2013 at 12:26pm

physics
An astronaut on a distant planet wants to determine its acceleration due to gravity. The astronaut throws a rock straight up with a velocity of + 15.5 m/s and measures a time of 13.9 s before the rock returns to his hand. What is the acceleration (magnitude and direction) due...
Monday, June 17, 2013 at 12:22pm

physics
A dynamite blast at a quarry launches a rock straight upward, and 1.9 s later it is rising at a rate of 14 m/s. Assuming air resistance has no effect on the rock, calculate its speed (a) at launch and (b) 5.6 s after launch.
Monday, June 17, 2013 at 12:09pm

physics
A woman on a bridge 81.6 m high sees a raft floating at a constant speed on the river below. She drops a stone from rest in an attempt to hit the raft. The stone is released when the raft has 9.13 m more to travel before passing under the bridge. The stone hits the water 4.30...
Monday, June 17, 2013 at 11:57am

physics
A thin, massless, horizontal pipe rotates about a vertical axis with angular speed ω as shown in the figure. A small bug, located at a distance r from the axis, starts crawling inside the pipe at constant speed v (relative to the pipe). Because of the bug, the motor must ...
Monday, June 17, 2013 at 11:41am

Physics
If an object is thrown in an upward direction from the top of a building 160 ft high at an initial speed of 30 mi/h, what is its final speed when it hits the ground?
Monday, June 17, 2013 at 10:01am

physics
from the first law of thympdynsmics, show that in the isothermal expansion of comprrssion of an ideal gas, the heat energy entering the system is equal to the work done by the gas and that these are RTln(V2- V1)
Monday, June 17, 2013 at 8:30am

physics
what is meant by liquefaction of gases? can hydrogen be liquefied by compression at the temperature of liquid air?
Monday, June 17, 2013 at 8:17am

Physics
solve physics question. a train moves 3.6km from rest to rest in 3minutes. the greatest speed is 90km/h, and the acceleration and retardation are uniform. find the distance travelled at full speed.
Monday, June 17, 2013 at 8:05am

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