Tuesday

August 4, 2015

August 4, 2015

**physics**

A 200 g model rocket is observed to rise 100 m above the ground after launch. What must have been the launch speed of the rocket at the ground?
*Thursday, June 25, 2015 by idnchfywek*

**Physics**

What is the relative humidity on a 25.0 °C day when the air contains 14 g/m3 of water vapor?
*Thursday, June 25, 2015 by Donnie*

**physics**

I have no idea. Please help. Thank you. The drawing shows a sulfur dioxide molecule. It consists of two oxygen atoms and a sulfur atom. A sulfur atom is twice as massive as an oxygen atom. Using this information and the data provided in the drawing, find (a) the x coordinate ...
*Thursday, June 25, 2015 by Lola*

**Physics**

A box is sliding down an incline tilted at an angle of 2.14° above horizontal. The box is sliding down the incline at a speed of 5.15 m/s. The coefficient of kinetic friction between the box and the incline is 0.387. How far does the box slide down the incline before ...
*Thursday, June 25, 2015 by Jen*

**Science physics**

a machine was used to lift a load of 30N through a distance of 2metres. the effort applied was 10N through a distance of 8metres. calculate the mechanical advantage
*Thursday, June 25, 2015 by Arnold*

**physics**

a screen is placed at a distance of 1.5 m from a narrow slit. the slit is illuminated by light of wavelength 6000 angstrom if the first minimum on either side of the central maximum is at a distance of 5 mm from , find the width of the slit
*Thursday, June 25, 2015 by Snehal Semwal*

**Physics**

Galileo’s law of falling bodies states that the rate of fall caused by gravity is the same for all objects, regardless of weight. This means that all objects have a free-falling acceleration of 9.8m/s2. However, a significant contradiction of this theory is the fact that ...
*Thursday, June 25, 2015 by Aurora*

**Physics**

Would a feather have more air resistance than a lump of lead?
*Thursday, June 25, 2015 by Emily*

**physics**

Ican Flye performs the infamous "Triple Lindy" dive from a point 15 m above water. a. If he starts his dive with no vertical velocity, how long will it take him to hit the water? b. How fast will he be traveling vertically when he hits the water? c. If he hits the ...
*Thursday, June 25, 2015 by Anonymous*

**Physics**

A 2.0 kg block of iron slides along a floor, decreasing its speed from 4.0 m/s to 1.0 m/s. a) How much work does the frictional resistance of the floor do on the block? b) If the reduction in velocity occurred over a distance of 10 m, what was the force of friction acting on ...
*Wednesday, June 24, 2015 by idnchfywek*

**physics**

7. An airplane has a gun that fires bullets straight ahead at the speed of 600 miles per hour when tested on the ground while the plane is stationary. The plane takes off and flies east at 600 miles per hour. Explain whether each of the following is possible for the pilot to ...
*Wednesday, June 24, 2015 by allexelle*

**physics**

If a freely falling rock were equipped with a speedometer, by how much would its speed readings increase with each second IF it were on a planet where g = 20 m/s2? Show all work leading to your answer.
*Wednesday, June 24, 2015 by allexelle*

**physics**

a ball is projected horizontally with speed u from a tower. 4 seconds after the throw it's velocity is at 45¡ã with horizontal. How long after projection, the velocity is at 37¡ã with horizontal?
*Wednesday, June 24, 2015 by SR*

**Physics - Equalibrium**

Three Fixed pulleys with a common center have the following radi of Ra=16cm, Rb=24cm and Rc=36cm with the applied forces <- Fc; /Fa (pointing southwest); and Fb (pointing southeast). Find the Resultant Torque given Fa=25N; Fb=75N; and Fc=120N.
*Wednesday, June 24, 2015 by Nathan*

**Physics**

A 45 kg cart is pushed up a ramp a length of 5.8 m from rest, attaining a speed of 2.6 m/s at the top of the ramp, which is 1.7 m high. The coefficient of friction between the cart and the ramp is 0.13. a) Determine the work done against: 1) gravity 2) inertia 3) friction. b) ...
*Wednesday, June 24, 2015 by jdemxkslwid*

**physics**

I have no way to solve this question. help me please The drawing shows a sulfur dioxide molecule. It consists of two oxygen atoms and a sulfur atom. A sulfur atom is twice as massive as an oxygen atom. Using this information and the data provided in the drawing, find (a) the x...
*Wednesday, June 24, 2015 by Lola*

**Physics **

A 50kg sign for a local business is hung from a bar which meets a wall at right angles as shown in figure 1. The bar is 1.5 meters long, and it's mass may be neglected. The center of mass of th sign is 1.0 meters from the wall (but .50 meters from the tip of the cable) as ...
*Wednesday, June 24, 2015 by David*

**Physics**

a 1.92 kg ball is connected by means of two massless strings, each of length L = 1.69 m, to a vertical, rotating rod. The strings are tied to the rod with separation d = 1.69 m and are taut. The tension in the upper string is 51.0 N. What are (a) the tension in the lower ...
*Wednesday, June 24, 2015 by Jeus*

**Physics**

For centripetal acceleration, if the radius increases, does that mean the angle is decreasing?
*Wednesday, June 24, 2015 by Emily*

**Physics**

The ride drops riders from the top of a tall tower and let's them free fall for a short time before bringing them to a stop. For the riders' safety, you must make sure the riders do not experience an acceleration greate than 2g. Assume the riders have a constant ...
*Wednesday, June 24, 2015 by Rolf*

**Physics**

if the distance and height of a track increase, does the car's accepted velocity and acceleration increase?
*Wednesday, June 24, 2015 by Tayla*

**Physics**

The speed of a projectile when it reaches its maximum height is 0.42 times its speed when it is at half its maximum height. What is the initial projection angle of the projectile?
*Wednesday, June 24, 2015 by Mark*

**physics**

You have a mass of 60 kg and run up some stairs that are 5 m high in 6 seconds. How much power did you produce?
*Wednesday, June 24, 2015 by abc123*

**Physics**

A object 0.25mm long is viewed through a converging lens.calculate the distance of the object from the lens,size of the image,power of the lens
*Tuesday, June 23, 2015 by Anonymous*

**physics**

You push against a steamer trunk at an angle of 33° with the horizontal . The trunk is on a flat floor and the coefficient of static friction between the trunk and floor is 0.55. The mass of the trunk is 43 kg. What is the minimum magnitude of force that will allow you to ...
*Tuesday, June 23, 2015 by alex*

**Physics**

Please help. To cool a hot bath containing 50L of water at 50 degrees Celsius down to 20degrees Celsius, what volume of cold water at 5 degrees Celsius would be needed? (in litres) and what mass of ice at 0 degrees celcius would be needed? i'm thinking about using q=...
*Tuesday, June 23, 2015 by Anonymous*

**physics**

A car with a mass of 1.2 × 103 kilograms starts from rest and attains a speed of 20 meters/second in 5 seconds. What net force acted on the car to cause that acceleration? 3.0 × 102 newtons 6.0 × 102 newtons 1.2 × 103 newtons 4.8 × 103 newtons 1.2...
*Monday, June 22, 2015 by sc*

**physics**

What amount of heat is required to raise the temperature of 20 grams of water from 10°C to 30°C? The specific heat of water is 4.18 J/g°C. 1200 joules 1500 joules 1700 joules 1900 joules 2000 joules
*Monday, June 22, 2015 by sc*

**physics**

what acceleration is imported to a football when the player kicked it with a force of 25 N mass of football 0.40kg
*Monday, June 22, 2015 by Anonymous*

**Physics**

A bottle with a volume of 196 U. S. fluid gallons is filled at the rate of 1.08 g/min. In years, how long does the filling take? (The density of water is 1 g/cm3 and 1 U.S. fluid gallon = 231 in3.) 196(231)/(1.08) The answer given was 1.31 years, not sure of the steps.
*Monday, June 22, 2015 by Ralph*

**physics**

A projectile of mass 1.000 kg is shot straight up with an initial speed of 23.0 m/s. (a) How high would it go if there were no air resistance? i got 26.99, which is correct (b) If the projectile rises to a maximum height of only 17.8 m, determine the magnitude of the average ...
*Sunday, June 21, 2015 by Lola*

**physics**

The drawing shows two boxes resting on frictionless ramps. One box is relatively light and sits on a steep ramp. The other box is heavier and rests on a ramp that is less steep. The boxes are released from rest at A and allowed to slide down the ramps. The two boxes have ...
*Sunday, June 21, 2015 by Lola*

**physics**

Two satellites, A and B, are in different circular orbits about the earth. The orbital speed of satellite A is thirty-four times that of satellite B. Find the ratio (TA/TB) of the periods of the satellites. Thank you!
*Sunday, June 21, 2015 by Lola*

**Physics **

A wheel has a radius of 3.1 m. How far (path length) does a point on the circumference travel if the wheel is rotated through the following angles, respectively? (a) 36° m (b) 36 rad m (c) 36 rev m
*Sunday, June 21, 2015 by Antonio*

**physics 1401**

If a vector A= -5.0x-4.0y and vector B = -3.0x+8.0y, then the magnitude of vector C= A-B is a. 13.4 b. 12.2 c. 148 d. 7.2 e. 4.5
*Sunday, June 21, 2015 by jcarrington*

**physics**

A 30-kg girl is bouncing on a trampoline. During a certain interval after she leaves the surface of the trampoline, her kinetic energy decreases to 205 J from 435 J. How high does she rise during this interval? Neglect air resistance.
*Sunday, June 21, 2015 by Lola*

**physics**

A 54.5-kg skateboarder starts out with a speed of 1.95 m/s. He does +80.0 J of work on himself by pushing with his feet against the ground. In addition, friction does -265 J of work on him. In both cases, the forces doing the work are nonconservative. The final speed of the ...
*Sunday, June 21, 2015 by Lola*

**physics**

A 50-kg box is being pushed a distance of 6.4 m across the floor by a force P with arrow whose magnitude is 154 N. The force P with arrow is parallel to the displacement of the box. The coefficient of kinetic friction is 0.24. Determine the work done on the box by each of the ...
*Sunday, June 21, 2015 by Lola*

**physics**

A baseball is thrown from the roof of a 24.0-m-tall building with an initial velocity of magnitude 10.0 m/s and directed at an angle of 53.1° above the horizontal.
*Sunday, June 21, 2015 by Anonymous*

**physics 1401**

A bullet is fired from a gun at 300 m/s. It hits the ground at 3s later. At what angle (in degrees) above the horizon was the bullet fired? (Assume no air resistance)
*Sunday, June 21, 2015 by jcarrington*

**Physics **

Two cars AandB travel along the same road in the Sam direction from the Same starting place.Car A maintains speed of 50km/h and car B 60km/h,but starts one hour later. how many hours will take for B to overtake A?
*Sunday, June 21, 2015 by nisha*

**Typos, math, physics**

Would everyone who posted math and physics problems this morning please go back and check for typos? It is difficult to guess what you mean and we do not have your text book.
*Sunday, June 21, 2015 by Damon*

**physics**

water heated to 50 degrees celsius is poured on our body during bathing what is equilibrium temperature of our body.spesific heat of water is 1.
*Sunday, June 21, 2015 by ramsaiteja*

**physics**

in einstein's famous equation e=mc^2, describing the relationship between matter and energy, the units for E are m=====>kg, c=====>m/s a) kg m/s b)kg m/s^2 c) m^2/s^2 d)kg m^2/s^2 I think its either B or D but indecisive...
*Saturday, June 20, 2015 by jcarrington*

**PHYSICS**

A BOATMAN ROWS TO A PLACE 48KM DISTANT AND BACK IN 14 HOURS; HE FINDS HE CAN ROW 4KM WITH THE STREAM IN THE SAME TIME AS 3KM AGAINST THE STREAM. FIND THE RATE OF THE STREAM? please help me :(
*Saturday, June 20, 2015 by CASS*

**PHYSICS**

A and B run around a circular track whose cicumference is 150m. when they run is opposite directions they meet every 5 seconds, but when they run in the same direction from the some point they are together every 25 seconds. what are their rates? ans. 18m/s and 12m/s please ...
*Saturday, June 20, 2015 by Natalie*

**PHYSICS**

A and B run around a circular track whose cicumference is 150m. when they run is opposite directions they meet every 5 seconds, but when they run in the same direction from the some point they are together every 25 seconds. what are their rates? ans. 18m/s and 12m/s can you ...
*Saturday, June 20, 2015 by Natalie*

**physics **

A small truck runs off the road and over a 100metre high cliff. It lands 50 metre from the base of the cliff. How long did it take for the truck to hit the ground
*Saturday, June 20, 2015 by andrew *

**Physics**

In class, we built a model of a roller coaster that would be one-hundredth of the size of the roller coaster if it were to be built in real life. On the model we built, 3.38G's were recorded. Would the amount of G-forces on the model roller coaster remain the same on the ...
*Saturday, June 20, 2015 by Isabelle*

**Physics**

Olympic diver Matthew Mitcham springs upward from a diving board that is 3.00 m above the water. He enters the water at a 79.0 degree angle with respect to the water surface, at a speed of 9.01 m/s. Determine the magnitude of his initial velocity. Determine the direction of ...
*Friday, June 19, 2015 by Rachel*

**PHYSICS**

It involves three masses, with mass 2 being the cart that can roll freely on a horizontal table. There is no friction anywhere. The cart system is let go with everything initially at rest. You are to find the accelerations for each of the three masses relative to the ground. (...
*Friday, June 19, 2015 by Lee M*

**physics**

car with a mass of 1.1 × 103 kilograms hits a stationary truck with a mass of 2.3 × 103 kilograms from the rear end. The initial velocity of the car is +22.0 meters/second. After the collision the velocity of the car is -11.0 meters/second. What is the velocity of...
*Friday, June 19, 2015 by se*

**physics**

A refrigerator with a weight of 1,127 newtons needs to be moved into a house using a ramp. The length of the ramp is 2.1 meters, and its height is 0.85 meters. What is the percentage efficiency if a force of 496 newtons is applied to the refrigerator? 44 percent 58 percent 64 ...
*Friday, June 19, 2015 by se*

**physics**

A box weighing 200 newtons is hanging from the ceiling. The value of 2 is 65°. Tensions T1 and T2 are 70 newtons and 130 newtons respectively. What is 1? 0.05° 25.2° 38.29° 76.58° 89.9°
*Friday, June 19, 2015 by se*

**Physics**

An air puck of mass 0.382 kg is tied to a string and allowed to revolve in a circle of radius 0.64 m on a horizontal, frictionless table. The other end of the string passes through a hole in the center of the table and a mass of 0.67 kg is tied to it. The suspended mass ...
*Friday, June 19, 2015 by Josh*

**physics**

Consider the static equilibrium diagram below. What is the net force acting along the positive x-axis?
*Friday, June 19, 2015 by bianca*

**Physics**

The ratio of velocities of sound in hydrogen and oxygen at stp is???
*Friday, June 19, 2015 by Roshan*

**Physics **

A mass is being pulled forward at a constant velocity of 3 m/s with a force of 15 N. The weight of the mass is 9.0 N. What applied force must be exerted so that the mass will accelerate to 14 m/s in 4.0 seconds. *Another one I don't understand. I even tried converting the ...
*Friday, June 19, 2015 by Austin*

**Physics **

A falling toy, mass 10.0 kg experiences an upward force due to air friction of 40.0 N. Find the acceleration of the toy. I honestly have no idea how to solve this question. Could someone please help me? :(
*Friday, June 19, 2015 by Austin*

**physics**

A body is projected at an angle of 30degree to the horizontal with a velocity of 150metre per seconds.Calculate the time it takes to reach the greatest height,take g=10metre per seconds square and neglect air resistance.
*Thursday, June 18, 2015 by scott*

**physics**

A student of weight 810 N was sent to another planet called Nerdland. If Nerdland has a mass that is 4 X the mass of the earth and a radius that is 1/2 the radius of the earth, what would be the mass in kg of the student when on Nerdland? what would be the weight in N of the ...
*Thursday, June 18, 2015 by Anonymous*

**PHYSICS**

27. Using energy considerations and assuming negligible air resistance, show that a rock thrown from a bridge 20.0 m above water with an initial speed of 15.0 m/s strikes the water with a speed of 24.8 m/s independent of the direction thrown.
*Thursday, June 18, 2015 by GILL*

**physics**

In the following situations identify the agent exerting the force and the object on which it acts .State the effect and kind of force in each case. a>Falling of rain drops. b>A horse pulling a cart. c>A car coming to rest once its engine is switched off. d>The ...
*Thursday, June 18, 2015 by deepti*

**Physics**

A typical tumor treated with radiotherapy may receive 400 Gy per 250g. How many disintegrations of caesium-137 atoms are required to provide that absorbed dose? Help would be appreciated!
*Thursday, June 18, 2015 by Please help!*

**physics**

A 115-N sign is supported by two ropes. One rope pulls up and to the right 26.5° above the horizontal with a tension T1, and the other rope pulls up and to the left 48.5° above the horizontal with a tension T2, as shown in the figure. Find the tensions T1 and T2.
*Wednesday, June 17, 2015 by chris browning*

**Physics**

An electron starts from one plate of a charged closely spaced (vertical) parallel plate arrangement with a velocity of 1.78×104m/s to the right. Its speed on reaching the other plate, 2.25cm away, is 3.63×104m/s . If the plates are square with an edge length of 26....
*Wednesday, June 17, 2015 by Yasamin*

**physics**

four resistor of resistances 1ohm,2ohm,3ohm,5ohm, are connected in series and afterwards in parallel.calculate the combined resistance in each case
*Wednesday, June 17, 2015 by Alade*

**Physics**

A sprinkler mounted on the ground sends out a jet of water at a 35∘ angle to the horizontal. The water leaves the nozzle at a speed of 15m/s . How far does the water travel before it hits the ground?
*Wednesday, June 17, 2015 by Tommy*

**Physics**

3. Johnny, of mass 65 kg, and Lucy, of mass 45 kg, are facing each other on roller blades. The coefficient of kinetic friction between the roller blades and concrete surface is 0.20. When Johnny pushes Lucy from rest he applies a force for 1.0 s. Lucy then slows down to a stop...
*Wednesday, June 17, 2015 by Furkan*

**Physics**

A photon having wavelength λ scatters off a free electron at A (see figure below), producing a second photon having wavelength λ'. This photon then scatters off another free electron at B, producing a third photon having wavelength λ'' and moving in ...
*Wednesday, June 17, 2015 by melanie*

**Physics**

2. An elephant is pushing, with 75 000 N of force, on two jeeps that are stuck in the mud. The elephant pushes on the first jeep (which is 2000 kg (2 SD)) and it, in turn, pushes on the second jeep (which is 1500 kg). The co-efficient of friction between the jeeps and the mud ...
*Wednesday, June 17, 2015 by Furkan*

**Physics**

Levon throws a ball straight upwards with an initial velocity of 15.0 m/s. a.How high will it reach? b.How long will it take unit his friend in a tree 5.0 m above him catches the ball? (he catches the ball on its way back down)
*Wednesday, June 17, 2015 by Furkan*

**Physics**

Jennifer is running the 100.0 m dash at track. She accelerates at a rate of 0.88 m/s2 for the first 45 m and then maintains this speed for the remainder of the race. How long will it take her to finish the race?
*Wednesday, June 17, 2015 by Furkan*

**Physics**

An elevator with a mass of 1.0 x 10^3 kg accelerates downward at 0.10 m/s^2. What would the force of tension be in the supporting elevator cable?
*Wednesday, June 17, 2015 by Furkan*

**Physics **

A mass, 5.0 kg is being pulled from rest with an applied force of 25N. The friction force is 10.0N. How far has it moved after 6.0s?
*Wednesday, June 17, 2015 by Furkan*

**Physics**

So we did this lab about how we are to measure the half life of the beta decay of indium 116 (the indium 116 is captured by indium 115 and undergoes beta decay to become tin 116. Since the Indium 116 I reused I understand that every time we use it, the indium 116 becomes a ...
*Wednesday, June 17, 2015 by Anna*

**physics**

A test rocket is launched vertically from ground level (y = 0 m), at time t = 0.0 s. The rocket engine provides constant upward acceleration during the burn phase. At the instant of engine burnout, the rocket has risen to 49 m and acquired a velocity of How long did the burn ...
*Wednesday, June 17, 2015 by gillies*

**physics**

a bullet moving with a velocity of 10m/s is stopped after penetrating the wooden plank of 4 cm of thickness. calculate acceleration of the bullet
*Wednesday, June 17, 2015 by nothing*

**physics**

identify tie force fields from the following : density field, temperatuse field, gravitational field, magnetic field, electrostatic field, electric field
*Tuesday, June 16, 2015 by Anonymous*

**physics**

the lines of force of a magnetic field do not cross. why is this so
*Tuesday, June 16, 2015 by alade olushola*

**Physics**

A projectile of mass 0.636 kg is shot from a cannon, at height 6.6 m, as shown in the figure, with an initial velocity vi having a horizontal component of 6.8 m/s. The projectile rises to a maximum height of ∆y above the end of the cannon’s barrel and strikes the ...
*Tuesday, June 16, 2015 by alex*

**physics**

A person goes to market,makes purchases and comes back at a constant slower speed.Draw displacement-time and velocity time graphs of the person
*Tuesday, June 16, 2015 by nikitha*

**physics**

A small bead of mass 100 g is able to slide along a frictionless wire. The wire is bent into a semicircle of radius 10 cm and rotates about a vertical axis with angular velocity 12.5 rad/s. (i) Draw a free body diagram depicting the forces acting on the bead (ii) For what ...
*Tuesday, June 16, 2015 by Khali Barkho*

**Physics **

Three blocks of mass 10kg, 20kg, 15kg respectively are being pushed in a row on along a horizontal surface with constant velocity by a force applied to the 10kg block.The coefficient of kinetic friction between each of the blocks and the surface is 0.18. What is the magnitude ...
*Tuesday, June 16, 2015 by Alex*

**Physics**

A man is dragging a trunk up the loading ramp of a mover's truck. The ramp has a slope angle of 20.0 degrees, and the man pulls upward with a force whose direction makes an angle of 30.0 degrees with the ramp. How large a force is necessary for the x component of the force...
*Monday, June 15, 2015 by Michaelanne*

**Physics**

Boxes A and B are in contact on a horizontal, frictionless surface. Box A has mass 21.0 kg and box B has mass 8.0 kg . A horizontal force of 100N is exerted on box A. What is the magnitude of the force that box A exerts on box B?
*Monday, June 15, 2015 by Sarah*

**Physics**

A rowboat is heading across a river at 2.4 m/s east. The current of the river is 1.7 m/s south. What is the rowboat's resultant velocity?
*Monday, June 15, 2015 by Kathy*

**Physics**

A body moved on x-axis at time t secs, the displacement of the particle from the origin is x-metre and the velocity of the particle is vm/s when t=0, s=0 and v=0. 1) given that the particle moves at a constant acceleration and that v=1 when t=4, find a)the value of ...
*Monday, June 15, 2015 by clement*

**physics**

A jetliner is traveling east from Seattle to Chicago, a distance of 1,750 miles. The jetliner travels at an average air speed of 620 mph relative to the air. At the jetliner's altitude, the wind is blowing 46 mph to the east. How long does the journey take?
*Monday, June 15, 2015 by alex*

**Physics**

The Golden Gate Bridge in San Francisco has a main span of length 1.28 km, one of the longest in the world. Imagine that a steel wire with this length and a cross-sectional area of 4.00 x 10-6 m^2 is laid on the bridge deck with its ends attached to the towers of the bridge, ...
*Monday, June 15, 2015 by Anna*

**physics**

An astronaut in a spacecraft looks out her window and observes a comet travel in the opposite direction at a relative speed of 237 m/s. The velocity of the spacecraft is 114 m/s directly away from the sun. What is the comet's velocity relative to the sun? Assume that ...
*Monday, June 15, 2015 by alex*

**physics**

A stone is thrown vertically upwards, reaches a highest point, and returns to the ground. When the stone is at the top of its path, its acceleration
*Monday, June 15, 2015 by alex*

**physics**

Hot air balloon A is rising upward a rate of 5.0 m/s. A passenger aboard balloon A observes balloon B rising upward at a relative rate of 7.5 m/s. What is the velocity of balloon B relative to the ground? Assume that up is positive.
*Monday, June 15, 2015 by alex*

**physics**

A test rocket is fired straight up from rest. The net acceleration is 20 m/s2 upward and continues for 4.0 seconds, at which time the rocket engines cease firing. What maximum elevation does the rocket reach?
*Monday, June 15, 2015 by alex*

**physics**

a man goes 10m towards north,then 20m towards east then displacement is what
*Monday, June 15, 2015 by sajid*

**Physics**

Find x and y components of a vector which is 10 units in length and 40 degrees below the +x axis. I honestly don't even know how to begin this problem .. Please help me !
*Monday, June 15, 2015 by Sasha*

**physics**

If R is the range for an angle of projectin 0f 15¤ wd the horizntl ' then the 0thr angle of projection for which the range is R 'is
*Monday, June 15, 2015 by dani*

**Physics **

What is the significance in the observation of discrete spectral lines in the emission spectrum of hydrogen??
*Monday, June 15, 2015 by Anna*

**physics**

A steel section of the Alaskan pipeline had a length of 58.5 m and a temperature of 18.0 °C when it was installed. What is its change in length when the temperature drops to a frigid -37.7 °C?
*Sunday, June 14, 2015 by ashley*

**physics**

The brass bar and the aluminum bar in the drawing are each attached to an immovable wall. At 29.0 °C the air gap between the rods is 1.93 x 10-3 m. At what temperature will the gap be closed?
*Sunday, June 14, 2015 by ashley*