Saturday

July 4, 2015

July 4, 2015

Number of results: 40,828

**Physics **

A motorist traveling at 15 m/s encounters a deer in the road 39 m ahead. If the maximum acceleration the vehicle’s brakes are capable of is −6 m/s2, what is the maximum reaction time of the motorist that will allow her or him to avoid hitting the deer? Answer in units of...
*October 2, 2011 by John*

**Physics**

A 1400 kg truck goes up a hilly road at a steady 60 km/h. The force of air resistance on the truck is 400 N. If the truck's engine supplies the enrgy to the drive wheels at a rate of 35 kW, what is the slope angle of the road? I get 7.1 please help, don't really get it.
*March 4, 2009 by Harold*

**Physics- drwls please help**

Please tell me where I am going wrong. A 59.5 kg person, running horizontally with a velocity of +3.90 m/s, jumps onto a 12.2 kg sled that is initially at rest. (a) Ignoring the effects of friction during the collision, find the velocity of the sled and person as they move ...
*March 3, 2007 by Mary*

**physics**

Two identical small marbles A and B can be seen. A is at rest while B moves towards A at uniform velocity. The track is smooth towards left of P while it offers a resistance of 0.1 m/s2 towards its right. After some time, the marbles are seen at rest 25cms apart. After ...
*September 20, 2014 by rahul*

**physics**

An entertainer juggles balls while doing other activities. In one act, she throws a ball vertically upward, and while it is in the air, she runs to and from a table 5.20m away at a constant speed of 2.40m/s, returning just in time to catch the falling ball. A) With what ...
*July 8, 2011 by izzy*

**physics**

A skier is accelerating down a 30.0 degrees hill at 1.80m/s^2. How long will it take her to reach the bottom of the hill, assuming she starts from rest and accelerates uniformly, if the elevation change is 375 m? Apparently the answer isn't 20.4 s... Can someone help me please?
*July 21, 2011 by Mika*

**physics**

when any block slides down a smooth incline which is unfixed then the incline moves back.WHY??
*February 21, 2010 by mohit*

**physics**

A 11.0 box is released on a 37 incline and accelerates down the incline at 0.25 .What is the coefficient of kinetic friction?
*October 15, 2010 by Anne*

**calculus**

the cross section of a 5-ft long trough is an isosceles trapezoid with a 2 foot lower base, a 3-foot upper base, and an altitude of 2 feet. water is running into the trough at a rate of 1 cubic foot per minute. how fast is the water level rising when the water is 1 foot deep?
*October 16, 2011 by rachel*

**math**

A tree casts a 25 foot shadow. At the same time of day, a 6 foot man standing near the tree casts a 9 foot shadow. What is the approximate height of the tree to the nearest foot?
*May 9, 2010 by miya*

**geomtry**

A tree casts a 25 foot shadow. At the same time of day, a 6 foot man standing near the tree casts a 9 foot shadow. What is the approximate height of the tree to the nearest foot?
*March 24, 2011 by najah*

**geomtry**

A tree casts a 25 foot shadow. At the same time of day, a 6 foot man standing near the tree casts a 9 foot shadow. What is the approximate height of the tree to the nearest foot?
*March 24, 2011 by najah*

**Math 7**

A tree casts a 50 foot shadow. At the same time of day, a 4 foot man standing near the tree casts a 10 foot shadow. What is the approximate height of the tree to the nearest foot?
*June 5, 2012 by Your Mom*

**Algerba**

Find slope and y-intercept of following equation y=-3 x -2 knowing the slope of intercept 5 formula is y=mx+b slope is m or -3 y=-3 or m (0) -2 m=slope 5 5 y-intercept = let x=o solve for y y=0-2 y=-2 You can tell by inspecting the equation in the y = mx + b form that the ...
*February 28, 2007 by Trusthim2*

**Macro econ**

Why does the supply of saving slope upward? Why does the investment demand slope downward? Identify the equilibrium in the market. If this is the standard curve, savers will save more when the rate of return, i.e. interest paid, is greater. Likewise, investors borrow less ...
*July 17, 2006 by Logan*

**Physics**

A small utility car is pulled along a straight section of railroad tracks by a rope. When the ropepulls the car for 10 seconds the car reaches a final speed, after starting from rest, of 8m/s. Now the situation is modified slightly so that the rope pulls, just as hard as in ...
*February 13, 2011 by John*

**Physics 1**

A mass of 17 kg is placed on a frictionless incline which is inclined at an angle of 59 degrees above the horizontal. It is held in place by a rope which is attached to a wall at the top of the incline. The rope is angled 17 degrees above the direction parallel to the incline...
*September 30, 2011 by Jon*

**Physics**

A mass of 11 kg is placed on a frictionless incline which is inclined at an angle of 69 degrees above the horizontal. It is held in place by a rope which is attached to a wall at the top of the incline. The rope is angled 13 degrees above the direction parallel to the incline...
*October 5, 2011 by Tina*

**Physics**

A block of mass m = 5.9 kg is pulled up a è = 21° incline as in the figure with a force of magnitude F = 34 N. (a) Find the acceleration of the block if the incline is frictionless. 1 Your response differs from the correct answer by more than 10%. Double check your ...
*October 7, 2011 by Imani*

**Physics**

A sphere of radius 20 cm and mass 1.2 kg rolls without slipping down a 30 degree incline that is 10 m long. a) Calculare the translational and rotational speeds of the sphere when it reaches the bottom. Assume it starts from rest, and first solve for each speed symbolically, ...
*April 20, 2010 by Alley*

**physics**

A 7 kg block is pushed by an external force against a spring with spring constant 124 N/m until the spring is compressed by 2.1 m from its uncompressed length (x = 0). The block rests on a horizontal plane that has a coefficient of kinetic friction of 0.7 but is NOT attached ...
*January 5, 2014 by Name*

**physics**

an object moves along a circle of radius r. its start froam A and reaches B. what is the path length? what is the displacement?
*July 1, 2011 by Anonymous*

**Precalculus **

A 28 foot ladder just reaches the top of a building and forms an angle at 44. 4 degrees with the wall of the building. How many feet is the building tall?
*July 2, 2013 by Jeanette*

**calculus**

given the velocity of a particle traveling along the y-axis by v(t)=tsin(t^2)
*February 22, 2015 by sam*

**Physics**

A ski trail makes a vertical descent of 78.0 m (as shown in the figure below ). A novice skier, unable to control his speed, skis down this trail and is lucky enough not to hit any trees. If the skier is moving at 12.1 m/s at the bottom of the trail, calculate the total work ...
*March 8, 2010 by Sarah*

**physics**

A 800·kg elevator is attached to a cable whose tension is 7800·N. Which of the following statements could describe the motion of the elevator? Choose all that apply. slowing down as it moves upward moving upward at constant speed speeding up as it moves downward slowing down ...
*January 17, 2013 by wally*

**Physics**

Sally Skier skiis down a rough ice covered 10.0 m high incline into a smooth bowl of radius 4.0 m. Sally starts her descent with a speed of 3.0 m/s at the top of the hill and arrives at the bottom of the bowl (point B) with a speed of 10.3 m/s. Sally has a mass of 65.0 kg. a. ...
*December 12, 2011 by Kim*

**Physics**

Your friend's car is parked on a cliff overlooking the ocean on an incline that makes an angle of 16.9° below the horizontal. The brakes fail, and the car rolls from rest down the incline for a distance of 36.3 m to the edge of the cliff, which is 61.1 m above the ocean, and, ...
*January 28, 2012 by Matthew*

**physics**

A harmonic wave is traveling along a rope. The oscillator that generates the wave completes 40.0 vibrations in 30.0 s. A given crest of the wave travels 425 cm along the rope in a period of 10.0 s.What is the wavelength? Show all of your work plz. i know the answer is 0.319 m ...
*May 11, 2011 by Anonymous*

**physics**

a blockof mass 100 kg tied to a donkey that moves with constant accelaration of 20centimeter over second squared up a 30 degrees incline. what is the force with which the donkey pulls on the block parallel to the incline? The coefficient of kinetic friction between the kinetic...
*May 4, 2010 by dai*

**physics**

A ball is thrown vertically upward with a speed of 26.8 m/s from a height of 1.9 m. How long does the ball take to hit the ground after it reaches its highest point?
*September 28, 2011 by Kelsi*

**physics**

A diver springs upward with an initial speed of 2.58 m/s from a 3.0-m board. (a) Find the velocity with which he strikes the water.(b) What is the highest point he reaches above the water?
*January 28, 2014 by Anonymous*

**Physics**

A stone is thrown vertically upward with a speed of 18.0 m/s. (a)How fast is it moving when it reaches a height of 11.0 m? (b)How long is required to reach this height ? (c)Why are there two answers to (b)?
*August 2, 2014 by Anonymous*

**physics**

A centrifuge is a common laboratory instrument that separates components of differing densities in solution. This is accomplished by spinning a sample around in a circle with a large angular speed. Suppose that after a centrifuge in a medical laboratory is turned off, it ...
*November 3, 2011 by marie*

**Calculus, AntiDerivatives**

I need help with this problem: A car traveling at 43 ft/sec decelerates at a constant 5 ft per second squared. How many feet does the car travel before coming to a complete stop? I'm not sure where to start, i know how to find antiDerivatives, but i dont even know the equation...
*November 23, 2006 by Mike*

**algebra**

If a pine cone is projected upward at a velocity of 16ft/sec from the top of a 96-foot pine tree, then how long does it take to reach the earth?
*June 13, 2012 by Anonymous*

**physics**

a foot ball is thrown upward with an angle of 30 degree with respect to the horizantal .to throw a 40meter pass what must be the intial speed of the ball?
*October 17, 2014 by ayan*

**physics**

A car sits in an entrance ramp to a freeway, waiting for a break in the traffic. The driver sees a small gap between a van and an 18-wheel truck and accelerates with constant acceleration along the ramp and onto the freeway. The car starts from rest, moves in a straight line, ...
*September 29, 2013 by Emma*

**Physics**

The Speed of train is reduced from 60km/h at the same time as it travels a distance of 450 m, If the retardation is uniform , find how much further it will travel (approx) before coming to rest? Answer is 30m but how? See my solution , i solved it in two ways . 1: Vi=16 m / s...
*October 28, 2014 by Shahab Mirza*

**geometry**

i don't get how to do slope i know the equation but it never comes out right...do you have any advice to help me b/c i ask some people and they don't get it either and we have a test tomorrow? CAn you give us a specific example? Well slope is very simple.All you have to do is ...
*October 9, 2006 by megg*

**bobpursley**

I had ask this question of you before but I didn't understand your response. Can you please clearify further. The question is: a skateboarder moving at v = 5 m/s along a horizontal section of a track that is slanted upward by 48° above the horizontal at its end, which is h = 0...
*February 27, 2007 by Mary*

**physics**

A person is riding a bicycle, the wheels of a bicycle have an angular velocity of +20.5 rad/s. Then, the brakes are applied. In coming to rest, each wheel makes an angular displacement of +12.0 revolutions. (a) How much time does it take for the bike to come to rest? (b) What ...
*November 10, 2010 by sean*

**physics**

A person is riding a bicycle, the wheels of a bicycle have an angular velocity of +24.0 rad/s. Then, the brakes are applied. In coming to rest, each wheel makes an angular displacement of +16.0 revolutions. (a) How much time does it take for the bike to come to rest? s (b) ...
*November 17, 2011 by Taylor*

**physics**

A 75g person on skis is going down a hill sloped at an angle 30.the coefficient of kinetic friction between the skis and the snow is 0.15.how fast is the skier going 10s after starting from rest?
*November 6, 2011 by Anonymous*

**physics**

A skier of mass 70kg is pulled up a slope by a motor-driven cable. The acceleration of gravity is 9.8m/s^2. How much work is required to pull him 60m up a 30.7º slope (frictionless) at a constant speed of 3 m/s? answer in units of kJ. In this question, I think I gotta use mgh ...
*September 17, 2006 by puff puff*

**Physics**

A solid ball and a hollow ball, each with a mass of 2 kg and radius of 0.1 m, start from rest and roll down a ramp of length 2 m at an incline of 34°. An ice cube of the same mass slides without friction down the same ramp. What is the speed of the solid ball at the bottom of ...
*June 18, 2012 by James*

**Algebra**

I have an assignment that asks me to write an equation in slope-intercept, point-slope, or standard form for the information given and to explain why the chosen form would be best. Below is the information given. 1. passing through (-1,4) and (-5,2) 2. that has slope 2 and y ...
*January 2, 2014 by Anonymous*

**PHYSICS**

A 16 kg block slides down a 30 degree frictionless incline where it is stopped by a strong Hook's Law spring at the bottom. The spring constant is k = 9.8 x10^4 N/m. If the block slides 9 m from the point where it was released (from rest) to the point where it comes to rest ...
*April 20, 2010 by Jason*

**physics**

A mass of 11 kg is placed on a frictionless incline which is inclined at an angle of 69 degrees above the horizontal. It is held in place by a rope which is attached to a wall at the top of the incline. The rope is angled 13 degrees above the direction parallel to the incline...
*October 6, 2011 by Kaleigh*

**PHYSICS HELP PLEASE !!!!!**

A 21 kg object is placed on an incline with friction. The incline is raised slowly from zero degrees and at 60.71 degrees, the object begins to slide down the incline. What is the coefficient of static friction? Be as accurate as possible with your answer and be sure to enter ...
*October 25, 2011 by Amanda *

**PHYSICS HELP PLEASE !!!!!**

A 21 kg object is placed on an incline with friction. The incline is raised slowly from zero degrees and at 60.71 degrees, the object begins to slide down the incline. What is the coefficient of static friction? Be as accurate as possible with your answer and be sure to enter ...
*October 25, 2011 by Amanda *

**AP Physics**

a 45 kg object slides down an uneven frictionless incline from rest without rotating. What is its speed after it travels 2.5 meters vertically
*October 30, 2010 by Asim*

**physics**

If 4.5 kg object is sitting at rest on a 30 degree incline that has a coefficient of static friction of .19, what is the net force down the plane? Does it start sliding?
*February 19, 2013 by Aaron*

**pysics.**

What is the minimum work needed to push a 975 kg car 230 m up along a 17.5° incline? Assume the effective coefficient of friction retarding the car is 0.20?
*October 12, 2009 by Joe*

**Physics**

A toy slides down an inclined plane which makes an angle of 60 degrees with the horizontal. It starts from rest and achieves a final velocity of 8 m/s in 5 seconds at the bottom of the plane. a. What is the acceleration down the plane? b. What is the distance along the plane ...
*November 2, 2013 by Tsunayoshi*

**Grammar **

Circle the adjectives that can be used with the nouns on the right . 1)upward 2)growing 3)recent (Problem) 1)steady 2)severe 3)reliable. (Supply) 1)available 2)increasing 3)public. (Concern) 1)immediate 2)effective 3)sufficient. (Solution) 1)affordable 2)rising 3)rapid. (...
*June 3, 2013 by Maryam*

**physics**

A 650kg elevator starts from rest. It moves upward for 3s with constant acceleration until it reases its cruising speed, 1.75m/s. (a) what is the average power of the elevator motor during this period? (b) How does this compare with its power during an upward cruise with ...
*October 28, 2007 by Anonymous*

**PHYSICS**

An entertainer juggles balls while doing other activities. In one act, she throws a ball vertically upward, and while it is in the air, she runs to and from a table 5.50m away at a constant speed of 2.50m/s, returning just in time to catch the falling ball. (a)With what ...
*July 13, 2010 by Francis*

**physics**

Search: A person is riding a bicycle, the wheels of a bicycle have an angular velocity of +18.0 rad/s. Then, the brakes are applied. In coming to rest, each wheel makes an angular displacement of +11.0 revolutions. How much time does it take for the bike to come to rest? What ...
*February 25, 2011 by Taylor*

**physics**

A 23.0 kg box is released on a 39.0° incline and accelerates down the incline at 0.268 m/s2. Find the friction force impeding its motion.
*March 1, 2011 by md8*

**Scientific studies**

A stone is thrown vertically upward with a speed of (a) How fast is it moving when it reaches a height of 11.0 m? (b) How long is required to reach this height? (c) Why are there two answers to (b)?
*February 17, 2010 by Aly*

**Physics**

A rok is thrown 24 meters/sec upward and lands in a 10 meter deep hole. How long is the rock in the air until it reaches the bottom of the hole?
*August 26, 2012 by Alex*

**physics**

A ball of mass .15 kg and a radius of .24 m is at the top of a 3.5 m tall hill with a 25 degree incline. What is the velocity of the ball as it reaches the bottom of the hill if it (a) rolls without slipping? (b)slips without rolling?
*October 28, 2010 by Anonymous*

**Physics**

A physics book slides off a horizontal tabletop with a speed of 1.10m/s . It strikes the floor in 0.350s . Ignore air resistance. The height of the tabletop above th floor is .600m.The horizontal distance from the edge of the table to the point where the book strikes the floor...
*October 15, 2010 by Kara*

**Physics**

A physics book slides off a horizontal tabletop with a speed of 1.10m/s . It strikes the floor in 0.350s . Ignore air resistance. The height of the tabletop above th floor is .600m.The horizontal distance from the edge of the table to the point where the book strikes the floor...
*October 15, 2010 by Sam*

**physics**

There is a block on top of an incline plane. The incline is going down to the right. The angle to the right of the 90 is 36.9 degree. There is a force pushing on it from the left. Find the applied force (F) needed to prevent the block from sliding down the incline; ignore ...
*June 26, 2011 by k9*

**math**

jim's 10-foot garage casts a 7-foot shadow. his house has a 17.5-foot shawdow. how tall is his house
*May 23, 2011 by selena*

**Physics**

A block with mass m = 2.00kg is placed against a spring on a frictionless incline with angle (30 degrees). (The block is not attached to the spring.) The spring with spring constant k = 19.6 N/cm, is compressed 20.0 cm and then released. a.) What is the elastic potential ...
*October 31, 2010 by Scott*

**PHYSICS**

An electron is initially at rest in, but not on the axis of, a solenoid that is carrying a steady current I directed as shown in the cross section below (counterclockwise). The electron is initially at rest on the -x axis. The current in the solenoid is suddenly increased to ...
*December 17, 2013 by asha*

**physics**

You're quietly sitting by a street one day, enjoying the sun, when you notice a speeding car traveling at 20 m/s down the street. The driver notices that there's a stop sign in the street and hits the brakes 40 m before the stop sign, coming to a stop right at the sign itself...
*May 20, 2013 by hemant*

**Physics**

A small block slides along a track from one level to a higher level, by moving through an intermediate valley (see Figure). The track is frictionless until the block reaches the higher level. There a frictional force stops the block in a distance d. Assume that the block's ...
*December 26, 2013 by George*

**physics**

A rock is given a KE of 2.00*10^4 J when it is launched vertically upward. If the rock reaches a height of 50m determine the mass of the rock.
*January 6, 2015 by moooose*

**Physics**

Mass 1 with a mass of 28.5 kg starts at rest at the top of a frictionless from a height of 17 meters. It then slides down the incline and moves over a horizontal frictionless surface and collides inelastically (head on) with mass 2 which is of unknown mass. After the ...
*November 15, 2012 by Chelsea*

**physics **

What is the minimum work needed to push a 950 kg car 890 m up along a 8.0 degree incline? Assume the effective coefficient of friction retarding the car is 0.22.
*October 10, 2011 by Luke *

**College Physics**

A block with mass m = 2.00kg is placed against a spring on a frictionless incline with angle (30 degrees). (The block is not attached to the spring.) The spring with spring constant k = 19.6 N/cm, is compressed 20.0 cm and then released. a.) What is the elastic potential ...
*October 31, 2010 by Scott*

**physics**

Starting from rest, a crate of mass m is pushed up a frictionless slope of angle (theta) by a horizontal force of magnitude F. Use work and energy to find an expression for the crate's speed v when it is at height h above the bottom of the slope. Express your answer in terms ...
*November 10, 2012 by Ohimai*

**physics**

A m = 2.51 kg mass starts from rest and slides a distance d down a frictionless theta = 34.6° incline. While sliding, it comes into contact with an unstressed spring of negligible mass. The mass slides an additional 0.220 m as it is brought momentarily to rest by compression ...
*October 31, 2009 by Anonymous*

**physics**

You have designed a rocket to be used to sample the local atmosphere for pollution. It is fired vertically with a constant upward acceleration of 17 m/s2. After 20 s, the engine shuts off and the rocket continues rising (in freefall) for a while. (Neglect any effects due to ...
*August 9, 2014 by Danielle*

**physics**

An ambulance is traveling east at 60.7 m/s. Behind it there is a car traveling along the same direction at 32.3 m/s. The ambulance driver hears his siren at a frequency of 521 Hz. At what frequency does the driver of the car hear the ambulance’s siren? The velocity of sound in...
*January 26, 2014 by Need answer by 10pm*

**Physics**

"An alpha particle (a helium nucleus) is traveling along the positive x-axis at 1 250 m/s when it enters a cylindrical tube of radius 0.500 m centered on the x axis. Inside the tube is a uniform electric field of 4.50 X 10^-4 N/C pointing in the negative y direction. How far ...
*February 21, 2011 by Anonymous*

**algebra 2**

A skier has decided that on each trip down a slope, she will do 2 more jumps than before. On her first trip she did 6 jumps. Derive the sigma notation that shows how many total jumps she attempts from her fourth trip down the hill through her twelfth trip. Then solve for how ...
*October 20, 2014 by Please Help Me*

**Math**

A skier has decided that on each trip down a slope, she will do 2 more jumps than before. On her first trip she did 6 jumps. Derive the sigma notation that shows how many total jumps she attempts from her fourth trip down the hill through her twelfth trip. Then solve for how ...
*October 20, 2014 by Take a look Please*

**Physics**

A car is parked on a cliff overlooking the ocean on an incline that makes an angle of 22◦ below the horizontal. The negligent driver leaves the car in neutral, and the emergency brakes are defective. The car rolls from rest down the incline with a constant acceleration ...
*October 23, 2013 by John*

**physics**

a block moves up 45degree incline w/ constant speed under the action of a force of 15n applied parallel to the incline.If the coefficient of kinetic friction is 0.3, determine the weight of the block and minimum force required to allow the block to move down the incline at ...
*March 6, 2014 by kmae*

**Geometry**

I need help in this problem: A 14-foot ladder is leaning against a house so that its top touches the top of the wall. the bottom of the ladder is 8 feet away from the wall. which of these can be used to find the height of the wall? A. in a right triangle with 14-foot leg and ...
*March 27, 2014 by Alex*

**11th grade**

A 16.0 kg box is released on a 39.0° incline and accelerates down the incline at 0.267 m/s2. Find the friction force impeding its motion
*November 27, 2010 by Anonymous*

**Physics**

Determine the acceleration of a 1500 kg automobile that rolls down an incline of 30° from the horizontal if a coefficient of friction between the tires and the incline is 0.12
*June 10, 2014 by Corey Brown*

**Physics**

In the flying ski jump, a skier acquires a speed of about 62 mph (this ended up being 27.7 m/s) by racing down a steep hill and then lifts off into the air off of a horizontal ramp. Beyond the ramp, the ground slopes at an angle of 45 degrees. a) Predict the distance downslope...
*September 6, 2013 by Lawon*

**physics**

Fred the otter climbed to the top of an inclined plane. His friend, Giselle the giraffe, suggested that he was so small that gravity would ignore him and he would be unable to slide down. "On the contrary", said Fred, "Since this slope makes an angle of 48.4 degrees with the ...
*November 13, 2012 by swag*

**physics**

Fred the otter climbed to the top of an inclined plane. His friend, Giselle the giraffe, suggested that he was so small that gravity would ignore him and he would be unable to slide down. "On the contrary", said Fred, "Since this slope makes an angle of 48.4 degrees with the ...
*November 13, 2012 by zach*

**Physics**

A 2 kg ball is rolled down a hill 25 m tall. When it reaches the bottom of the hill it is traveling at 15.1 m/s. How much energy was dissipated due to friction?
*March 4, 2014 by Tyler*

**science**

A ? is a channel along which water is continually flowing down a slope
*February 27, 2009 by alison*

**physics**

a 200 kg block was moved along an inclined plane to a height of 10m. during this process 3000J of energy was lost due to friction. a. calculate the efficiency of the inclined plane. b. what would the efficiency of the simple machine be if the incline were frictionless? c. how ...
*January 31, 2009 by april*

**math**

can someone help me set this up so i can solve. Problem #3 the posted speed limit for trucks along national route 3 is 35 MPH. how many kilometers will a convoy cover after 3.7 hours on the road traveling at the posted Problem # 5 IF the formula to figure volume for a cubic ...
*March 26, 2007 by jasmine20*

**College Physics I**

A helicopter traveling upward at 120 m/s drops a package from a height of 500 meters. To the nearest second how long does it take to hit the ground?
*August 26, 2012 by Dylan*

**Physics**

a 300kg piano is being lifted at a steady speed from ground level straight up to an apartment 10.0m above ground. The crane that is doing the lifting produces a steady power of 400 W. How much time does it take to lift the piano?
*November 25, 2008 by Delli*

**Analytic geometry - finding point by intersect lin**

I have a triangle ABC. The slope of AB is -1/ab, the slope of AC is -1/ac, and the slope of BC is -1/ac. My question is, I have 3 lines: Altitude from A to BC, altitude from B to AC, and altitude from C to AB. I know their slope because it is just -1/slope. But I want to know ...
*March 5, 2013 by Knights*

**physics**

A 40-kg sled rests at the top of a 34˚ incline that is 500 m long. If the coefficient of friction is 0.2, what will be the speed at the bottom of the slope? The 40-kg mass includes the mass of the person on the sled.
*March 31, 2012 by rahul patel*

**Physics**

Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 3.6 m/s2 for 4.5 seconds. It then continues at a constant speed for 7.3 seconds, before applying the brakes such that the car...
*January 6, 2014 by Shreyas*

**physics**

I am having so much trouble with this D: A rocket is traveling straight up from its launch pad. An observer 5.00 km from the launch pad notices that at one instant, she must tilt her telescope 45.0 degrees upward to see the rocket. 10.0 seconds later, she must tilt her rocket ...
*August 25, 2011 by Jasmine*