Total # Posts: 221
An outfielder throws a baseball with an initial speed of 30 m/s at an angle of 13° to the horizontal. The ball leaves his hand from a height of 1.75 m. How long is the ball in the air before it hits the ground?
May 21, 2012
This problem was done wrong. same equation but the answer was solved incorrectly. Your solving for v2. so 72 should be divided by the 208 not the other way around. The answer should be less the 1. around 0.346.
March 27, 2012
can you give me a picture lock and key diagrams. I need to make my own lock and key diagram. I dont know the difference between synthesis and hydrolosis so can you give me some pictures and label them if they are hydrolosis or synthesis.
February 16, 2012
A mole of air (80% Nitrogen, and 20% Oxygen by volume) at 298.15K is brought into contact with liquid water which has a vapor pressure of 3168Pa at this temperature. a) what is the volume of the dry air if the pressure is 1 bar? b) what is the final volume of the air saturated...
February 6, 2012
If a snowball melts so that its surface area decreases at a rate of 3 cm2/min, find the rate at which the diameter decreases when the diameter is 9 cm. (Give your answer correct to 4 decimal places.)
November 29, 2011
The force F (in Newtons) required to move a box of mass m kg in motion by pulling on an attached rope is F(x) = f m g/(cos(x))+ f (sin(x)) where x is the angle between the rope and the horizontal, f is the coefficient of static friction and g = 9.8 m/s^2. Find the angle x that...
November 14, 2011
Use the Mean Value Theorem to show: -x < sinx < x for all x > 0 (and where I have the inequalities, it's supposed to be less than or equal to for the first two and greater than or equal to for the last one, I just didn't know how to type it)
November 3, 2011
Alkali metals are so reactive that they react directly with water in the absence of acid. For Example... 2 K(s) + 2 H2O(l) ¨ 2 K+(aq) + 2 OH− (aq) + H2(g). How many milliliters of hydrogen will be evolved over water when 4.52 g K reacts with an excess of. H2O (l)?
October 12, 2011
A Person is riding a bike with wheels that have a 14 inch radius at 15 mph. The bicyclist rides over some gum which sticks in the tire, assume this is t=0. 1. Find a function that gives the height in inches above the ground of the gum, with input is second
March 30, 2011
The molar mass is an indirect relection of the polarizablity. Because molecules with higher molar masses often have more protons and thus more electrons the molecule will be more suseptable to polarizablity. Polarizing a molecule is deforming its electron cloud. Some molecules...
March 4, 2011
Use the equation PV=nRT (pressure times volume equals moles of gas times constant times temperature). Assuming you aren't with-holding information, the number of moles of gas and the temperature must remain the same, so the initial Pressure and Volume must be equal to the ...
March 3, 2011
Math - Nash equilibrium
Part 1 Consider a variant of electoral competition on the line that captures features of the US presidential election. Voters are divided between two states. State 1 has more electoral college votes than does state 2. The winner is the candidate who obtains the most electoral ...
February 28, 2011
You could definately check the boiling points to see if they are pure but that would kind of defeat the purpose of steam distillation. What compounds are you working with? Could you do some other test?
February 17, 2011
a rectangular-shaped garden has a length of 40 feet and a width of 15.how many more square feet of garden could be obtained by increasing both the length and width by 10 feet
February 14, 2011
A crow sits on a clothesline midway between two poles as shown. Each end of the rope makes an angle of θ = 16° below the horizontal where it connects to the pole. If the combined weight of the crow and the rope is 8.4 N, what is the tension in the rope?
February 14, 2011
A cube of ice is taken from the freezer at -9.5 degree Celsius and placed in a 99 g aluminum calorimeter filled with 327 g of water at room temperature of 20.0 degree celsius. The final situation is observed to be all water at 17.0 degree Celsius. What was the mass of the ice ...
January 18, 2011
the height of a projectile is modeled by the equation y=-2x^2+38x+10, where x is a time, in seconds, and y is height, in feet, During what interval of time, to the nearest tenth of a second, is the projectile at least 125 feet above ground
December 10, 2010
A 25 kg chair initially at rest on a horizontal floor requires 393 N horizontal force to set it in motion. Once the chair is in motion, a 301 N horizontal force keeps it moving at a constant velocity. a) Find the coefficient of static friction between teh chair and the floor. ...
November 18, 2010
Info. Tech (Computer Science)
1.)(a) CPU 1 has speed of 2.6 GH (steps per second) and runs a program which needs 10.9 T steps. (b) CPU 2 has speed of 2.2 GH and runs program which needs 7.3 T steps. ---How long does it take for CPU 1 and CPU 2 to finish the work? (Show all work!) 2.)How many more more 4 ...
November 17, 2010
11th grade Math
Two cars travel the same distance. The first car travels at a rate of 37 mph and reaches its destination in t hours. The second car travels at a rate of 54 mph and reaches its destination in 3 hours earlier than the first car. How long does it take for the first car to reach ...
November 3, 2010
A 69.5 kg painter is on a uniform 30.0 kg scaffold supported from above by ropes . There is a 5.0 kg pail of paint to one side, as shown. The scaffold is 6 m long. 1.0 m on both ends and 4 m in the middle. From the left end at 1.0 m to the pail is 1.0 m. How close to the end ...
November 3, 2010
Two particles are in a uniform electric field whose value is +4000 N/C. The mass and charge of particle 1 are m1 = 1.0x10-5 kg and q1 = -15 µC, while the corresponding values for particle 2 are m2 = 3.0 x10-5 kg and q2 = +35.0 µC. Initially the particles are at ...
October 4, 2010
A Carnot engine operates between 170°C and 20°C. How much ice can the engine melt from its exhaust after it has done 6.0 104 J of work? i need a step by step process. you don't have to give me the answer.
September 29, 2010
One gram of water changes from liquid to solid at a constant pressure of 1.00 atm and a constant temperature of 0°C. In the process, the volume changes from 0.60 cm3 to 1.14 cm3. Find the work done on the water? Find the change in the internal energy of the water?
September 29, 2010
A tennis player standing 11.5 m from the net hits the ball at 2.60° above the horizontal. To clear the net, the ball must rise at least 0.252 m. If the ball just clears the net at the apex of its trajectory, how fast was the ball moving when it left the racquet?
September 19, 2010
A rocket is fired straight up through the atmosphere from the South Pole, burning out at an altitude of 208 km when traveling at 5.8 km/s. (a) What maximum distance from Earth's surface does it travel before falling back to Earth? I know how to do the work, but i can't...
March 29, 2010
A rocket is fired straight up through the atmosphere from the South Pole, burning out at an altitude of 208 km when traveling at 5.8 km/s. (a) What maximum distance from Earth's surface does it travel before falling back to Earth?
March 26, 2010
A 755 N man stands in the middle of a frozen pond of radius 9.0 m. He is unable to get to the other side because of a lack of friction between his shoes and the ice. To overcome this difficulty, he throws his 1.2 kg physics textbook horizontally toward the north shore at a ...
March 1, 2010
While blowing its horn of f=524 Hz a car accelerates at 0.8m/s^2 the car starts from rest by your side and moves away. Find the time it taked for the frequency you hear to decrease by 5%. Hint: Dont forget to include the time it takes for sound to reach you any help would be ...
February 22, 2010
Tarzan, who weighs 820 N, swings from a cliff at the end of a 20.0 m vine that hangs from a high tree limb and initially makes an angle of 22.0° with the vertical. Assume that an x axis extends horizontally away from the cliff edge and a y axis extends upward. Immediately ...
February 21, 2010
A toy gun uses a spring to project a 5.3 g soft rubber sphere vertically. The spring constant is 8.0 N/m, the barrel of the gun is 15 cm long, and a constant frictional force of 0.032 N exists between barrel and projectile. How high does the projectile go if the spring was ...
February 19, 2010
A 80 kg diver steps off a 10 m tower and drops from rest straight down into the water. If he comes to rest 5.0 m beneath the surface, determine the average resistance force exerted on him by the water.
February 18, 2010
A horizontal force of 150 N is used to push a 33.0 kg packing crate a distance of 6.65 m on a rough horizontal surface. If the crate moves at constant speed and the work done is 997.5 joules. What is the coefficient of kinetic between the crate and the surface.
February 18, 2010
The answer is 433.719 joules. You find the sum of the x forces by taking 110*cos31.1 - 19.5*9.81*.156 which gives you 64.35 Newtons. You put that answer in the Work formula. Work equals force * distance so take 64.35*6.74 meters and you get your answer, 433.719 Joules.
February 18, 2010
I got all but this problem. A 0.145-kg baseball is pitched at 42.0 m/s. The batter hits it horizontally to the pitcher at 58 m/s. A. Find change in momentum? Is it =.145*58-(-.145*42)=1.45-kg m/s? B. If bat and ball are in contact for 4.6 x 10-4 s, what is average force ...
February 14, 2010
I got all but this problem, I A 0.145-kg baseball is pitched at 42.0 m/s. The batter hits it horizontally to the pitcher at 58 m/s. A. Find change in momentum? Is it =.145*58-(-.145*42)=1.45-kg m/s? B. If bat and ball are in contact for 4.6 x 10-4 s, what is average force ...
February 14, 2010
An ice skater spins with his arms outstretched. When he pulls his arms in and raises them above his head he spins much faster than before. Did a torque act on the ice skater? If not how could his angular velocity have increased?
February 12, 2010
As tradition has it, Santa Claus is coming on the 5th of December from Spain to the Netherlands to bring gifts to Dutch children. Help is needed to distribute the gifts for which the Santa Claus committee is hiring helpers, so-called Zwarte Pieten. There are two types of ...
December 30, 2009
Grade 12 Data Management
Two cards are drawn without replacement from a deck of 52 cards. a. What is the probability of drawning 2 aces? b. What are the odds in favour of drawing 2 honour cards? (A, K, Q, J, 10)
December 2, 2009
Although most salamanders have four legs, the aquatic salamander shown below resembles an eel. It lacks hind limbs and has very tiny forelimbs. Propose a hypothesis to explain how limbless salamanders evolved according to Darwin's theory of natural selection.
October 22, 2009