Friday

July 3, 2015

July 3, 2015

Total # Posts: 537

**Physics**

A student (m = 63 kg) falls freely from rest and strikes the ground. During the collision with the ground, he comes to rest in a time of 0.0120 s. The average force exerted on him by the ground is +17000. N, where the upward direction is taken to be the positive direction. ...
*November 12, 2012*

**Physics**

Suppose the surface (radius = r) of the space station in the figure is rotating at 38.6 m/s. What must be the value of r for the astronauts to weigh one-half of their earth-weight?
*November 7, 2012*

**Physics**

Two banked curves have the same radius. Curve A is banked at an angle of 11°, and curve B is banked at an angle of 16°. A car can travel around curve A without relying on friction at a speed of 18.5 m/s. At what speed can this car travel around curve B without relying ...
*November 7, 2012*

**Physics**

A "swing" ride at a carnival consists of chairs that are swung in a circle by 12.0 m cables attached to a vertical rotating pole, as the drawing shows. (è = 60.0°) Suppose the total mass of a chair and its occupant is 222 kg
*November 7, 2012*

**physics**

Each of the space shuttle's main engines is fed liquid hydrogen by a high-pressure pump. Turbine blades inside the pump rotate at 595 rev/s. A point on one of the blades traces out a circle with a radius of 0.02 m as the blade rotates. (a) What is the magnitude of the ...
*November 7, 2012*

**physics**

A satellite is in a circular orbit about the earth (ME = 5.98 1024 kg). The period of the satellite is 4.20 104 s. What is the speed at which the satellite travels?
*November 7, 2012*

**Physics**

A racetrack has the shape of an inverted cone, as the drawing shows. On this surface the cars race in circles that are parallel to the ground, and the surface is at an angle è = 20°. For a speed of 40 m/s, at what value of the distance d should a driver locate his ...
*November 7, 2012*

**Physics**

Two banked curves have the same radius. Curve A is banked at an angle of 11°, and curve B is banked at an angle of 16°. A car can travel around curve A without relying on friction at a speed of 18.5 m/s. At what speed can this car travel around curve B without relying ...
*November 7, 2012*

**Physics**

A block is hung by a string from the inside roof of a van. When the van goes straight ahead at a speed of 31 m/s, the block hangs vertically down. But when the van maintains this same speed around an unbanked curve (radius = 145 m), the block swings toward the outside of the ...
*November 7, 2012*

**Physics**

A stone has a mass of 6.00 10-3 kg and is wedged into the tread of an automobile tire, as the drawing shows. The coefficient of static friction between the stone and each side of the tread channel is 0.73. When the tire surface is rotating at a maximum speed of 17 m/s, the ...
*November 7, 2012*

**Physics**

The earth rotates once per day about an axis passing through the north and south poles, an axis that is perpendicular to the plane of the equator. Assuming the earth is a sphere with a radius of 6.38 106 m, determine the speed and centripetal acceleration of a person situated ...
*November 6, 2012*

**Physics**

The earth rotates once per day about an axis passing through the north and south poles, an axis that is perpendicular to the plane of the equator. Assuming the earth is a sphere with a radius of 6.38 106 m, determine the speed and centripetal acceleration of a person situated ...
*November 6, 2012*

**chem **

What is the total pressure of a mixture of 0.3 atm of F2, 0.5 atm of Cl2, and 0.8 atm of O2?
*November 5, 2012*

**chem **

Calculate the number of mol of helium in a 11.2 L balloon at 300 K and 1.00 atm of pressure ?
*November 5, 2012*

**chem **

If 10.0 mol of CO occupies a volume of 20.0 L what volume would 4.0 mol of CO occupy?
*November 5, 2012*

**Physics**

During a storm, a tree limb breaks off and comes to rest across a barbed wire fence at a point that is not in the middle between two fence posts. The limb exerts a downward force of 148 N on the wire. The left section of the wire makes an angle of 12° relative to the ...
*October 30, 2012*

**Physics**

The drawing shows three particles far away from any other objects and located on a straight line. The masses of these particles are mA = 363 kg, mB = 517 kg, and mC = 154 kg. Find the magnitude and direction of the net gravitational force acting on each of the three particles...
*October 30, 2012*

**math**

7x9=63
*October 16, 2012*

**enviromental**

Completely mixed flow ractor CSTR and plug flow reactor (PFR) may have significantly different efficiencies depending on the reaction order. This problem asks you to compare the relative reactor sizes required to ensure 99.0 % removal of wastewatwer pathogens. Wastewater from ...
*October 14, 2012*

**math**

Holy Waa!! Your dad is a loan shark.... call the cops!
*October 9, 2012*

**Phy I**

Two forces, 1 and 2, act on the 5.00 kg block shown in the drawing. The magnitudes of the forces are F1 = 47.5 N and F2 = 34.5 N. What is the horizontal acceleration (magnitude and direction) of the block?
*October 3, 2012*

**Math**

Suppose an odd function f has an inverse g. Prove that g is also odd.
*September 26, 2012*

**Math**

What is 6 less than half a number?
*September 23, 2012*

**geometry**

if AB=CD, AB is 12-y, CD = 3x-4y, BD = 18, AC = x+y, what is x, y, and AC
*September 15, 2012*

**calculus**

I need help with the following problem: From a point 50 meters from the bottom of a radio tower along level ground, the angle of elevation to the top of the tower is 67 degrees. What is the height of the tower?
*September 3, 2012*

**Calculus**

I need help with the following problem: You're in a hot air balloon with your support crew on the ground. Attached to the balloon are two tether cords of length 350 feet and 400 feet that your crew attached to the ground. These cords form an angle of 50 degrees where they ...
*September 3, 2012*

**calculus**

I need help with the following question: Which of the following is an example of a function whose derivative is always 3? Choices are: f(x) = x=3 f(x) = 5x+3 f (x) = 3x+5 f(x) = 3 Thank you.
*August 28, 2012*

**math**

I need help answering the following question: A road sign reads: "5% grade next 4 miles." What is the change in elevation from the lookout to the point four miles ahead (to the nearest foot)?
*August 26, 2012*

**math**

I need help with the following question: While fishing on a lake, you see a fish below water at a 25 degree angle with the surface, producing air bubbles on the surface of the water 20 feet ahead. How far away is the fish from the boat?
*August 26, 2012*

**Calculus**

Sorry - the total amount of fencing is 240 feet
*August 24, 2012*

**Calculus**

How do I find the total area of three connected equally sized pens built so as to maximize the area bounded?
*August 24, 2012*

**math**

out of 40 people,17 have brothers,22 have sisters and 9 have both.how many people have neither brothers nor sisters
*August 18, 2012*

**math**

sue has some ducks and some goats,if there are 36 legs altogether,what is the greatest number of goats possible
*August 18, 2012*

**math**

a number of teachers were to receive 6 pens each ,but needed 4 more pens for them to be equally divided.if each teacher received 9 pens, 25 more pens would be necessary.how many pens are there
*August 18, 2012*

**math**

my average results from the last 4 maths exams was 18 out of 25.what mark do i need in my fifth exam in order to increase the everage by 3%
*August 18, 2012*

**math**

a cube made up of some blocks and there are 12 cubes ,block a and b are removed from each other.how many blocks will remain in the 12 cubes altogether
*August 18, 2012*

**math**

a pool is filled with water in 6 hours at 100 m every hour. If 125 m could be filled every hour,the pool would be full at 11.00am.What was the latest possible time that the water could have started filling the pool
*August 11, 2012*

**math**

a large cogwheel contains 117 cogs, and a small one contains 52 cogs.if the large wheel revolves 20 times,find the amount of revolutions of the small wheel.
*August 11, 2012*

**math**

what is the next number of 3,4,8,17,33
*August 11, 2012*

**math**

a triangle,side ac is 3/5 of side ab,and is 23.1 m. side ab is 7/9 of side bc.angle b is 1.5 times larger than angle c,and angle a is twice the size of angle c.how many degrees is angle A
*August 11, 2012*

**math**

oout of 45 people ,37 caught the train,15 the bus,5 walked.how many caught both bus and train?
*August 11, 2012*

**math **

28 students,all of whom study either science,language or both.18 students study language and 14 study science.how many students study acience and language? and how many study only science?
*August 11, 2012*

**math**

there are 28 students,all of whom study either science,language or both,18 students study language and 14 study science.How many students study science and language?
*August 11, 2012*

**math**

6 builders worked 8 hours a day for 10 days to complete a job.If 8 builders worked 6 hours a day for 3 days,the remaining work has to be completed by 6 builders in 8 days.How many hours does each builder need to work each day?
*August 11, 2012*

**math**

6 builders worked 8 hours a day for 10 days to complete a job.If 8 builders worked 6 hours a day for 3 days,the remaining work has to be completed by 6 builders in 8 days.How many hours does each builder need to work each day?
*August 11, 2012*

**math **

how many grams are there in 1 km
*August 5, 2012*

**math**

3trucks are equal in weight to 2 trucks and 2 sedans.What fraction of the weight of a truck is the weight of a sedan
*August 5, 2012*

**math**

front wheels of a cart have a circumference of 3 metres.back wheels have a circumference of 4 metres.A white dot is painted on the rim of each wheel it touches the ground.the cart is then driven 100 metres.including the starting position,how many times will the white dots be ...
*August 4, 2012*

**math **

121 balls are placed in group of 7and 5 in basket.how many baskets 0f 7 were there?
*July 29, 2012*

**math**

how many words of 1;2;3 letters can be made from the letters in CART
*July 21, 2012*

**math **

the day is 1hour 18minutes longer than the night.how long is the day?
*July 5, 2012*

**math**

how to write 9.035 in expanded notation
*June 17, 2012*

**math**

complete these series,1,8,27,64,___,____
*June 17, 2012*

**math**

complete these series,1,8,27,64,___,____
*June 17, 2012*

**math**

twin primes have one composite number between them(e.g.5,7).write one pair of twin primes between number 20 and 40
*June 9, 2012*

**math**

label its dimensions after you rule a square the same area as this rectangle on the back of this sheet 16mm ,4mm
*June 9, 2012*

**math**

1/5 of 35 +16 equal?
*June 9, 2012*

**math**

how many times greater is the first 7 than second in 876574?
*June 9, 2012*

**math **

there are 3 shirts,2 caps,4 pairs of shorts.how many different outfits can wear ?(consisiting of one shirt,one pair of shorts and one cap
*June 9, 2012*

**math**

howmany degrees does a person turn who was facing north and now faces south?
*June 9, 2012*

**math**

there are 23 of? in 2.3
*June 3, 2012*

**math**

what is different between a decimal and a decimal point?
*June 3, 2012*

**math**

.in the decimal fractions0.1 and 0.02 the numeral 1 is ?
*June 2, 2012*

**math**

what fraction of 6cm is 15mm .
*June 2, 2012*

**math**

express64in3 different ways,using only index notation
*June 2, 2012*

**Physics**

An electric immersion heater is rated 5 A when connected to a 120V circuit. What is the resistance of the heater? If it takes 168 KJ to heat 500 ml of water from 20 deg C to boiling, how long does it take to heat the water?
*May 18, 2012*

**Physics**

Ahhh so its 120*7.5*50seconds 7.5 being the amps that the drill draws and 50 being the time and 120 being the voltage.
*May 18, 2012*

**Physics**

Hi bob, could you explain how you came to that calculation, please. As in where did the 1.5 come from, and the 50 joules(it was 50 seconds) I'm lost, could you help? Thanks
*May 18, 2012*

**Physics**

An electric drill operates at a potential difference of 120V and draws a current of 1.5 Amps. If it takes 50 seconds to drill a hole in a piece of steel,calculate the amount of electrical energy used by the drill in that time.
*May 18, 2012*

**Computer**

I have open office and can't find the symbols tab.. arghh
*May 18, 2012*

**Computer**

Hi Ms. Sue ... how do you make the small 3 by itself after the 10?
*May 18, 2012*

**Computer**

On a laptop, how do you get the 10 to the 3rd power? ( make a small 3 after the 10?)
*May 18, 2012*

**physics**

a 12 Volt car battery supplies 1.0 x 10^3 C of charge to the starter. How much energy is used to start the car? ( it's not 10 cubed, but 10 to the third power)
*May 18, 2012*

**physics 30**

an object is thrown from 1.5m above the ground with a velocity of 15m/s and at an angle of 25deg with the ground. using vectors and motion equations, determine how long the object will remain in the air before returning to the ground. ARGHHHHHH help please..
*May 13, 2012*

**Physics**

a 70g bag of potato chips contains 1.6MJ of energy. Working at your maximum power, how long would it take to burn this energy?
*May 6, 2012*

**Physics**

If I know the length of all 3 sides in a right angle triangle, how do I get the degrees of the other angles? Which formula do I use again?
*May 6, 2012*

**Physics 30**

a 2000kg car traveling east at 24m/sec enters an icy (frictionless) intersection and collides with a 3600kg truck traveling south at 10 m/sec. If they become coupled together in the collision, what is their velocity immediately after impact?
*May 1, 2012*

**math**

there are 3 arrays for 4, how many arrays can be drawn for each prime numbers
*April 29, 2012*

**math**

there are 122 houses,how many times does the digit 2 appear on the letterboxes?
*April 29, 2012*

**maath**

there are 3 arrays for 4.how many arrays can be drawn for each prime numbers
*April 29, 2012*

**Physics 30**

If a truck moving at 30km/hr accelerates at 2.5m/s^2 to 50 km/hr, what time (in sec) does it take? a. 2.22s b. 5.56s c. 8 s d. 28.8s
*April 20, 2012*

**algebra**

if the red river is 500 miles longer than the blue river. if the sum of their lengths is 5550 miles what is the length of each river
*April 16, 2012*

**algebra**

Can someone help me figure this out please? when you solve a system of equations by the substitution method, how do you determine whether the system of equations is inconsistent? thank you anyone
*March 18, 2012*

**algebra**

I need help. Can someone help me please. Explain how you can determine from the graph of a system of two linear equations in two variables whether it is an inconsistent system of equations. Thank you
*March 18, 2012*

**Physics**

(.50 kg )(35.7m/s^2) = ? kilograms meters per second squared
*March 17, 2012*

**calc**

by applying rolle's theorem, check whether it is possible that the function f(x) = x^5 + x -17 has two real roots. your reason is that if f(x) has two real roots then by rolle's theorem, f'(x) must be equal to what at certain value of x between these two roots, but...
*March 16, 2012*

**chemistry**

Carbon monoxide gas and hydrogen gas are mixed in a two liter flask. The reaction produces methanol gas as the only product. At equilibrium the Keq is 1.1 x 10-5. The flask initially held 6 grams of hydrogen and the equilibrium concentration of hydrogen is 0.1 M. How many ...
*March 12, 2012*

**Discete Math**

Show that there must be at least 90 ways to choose six integers from 1 to 15 so that all choices have the same sum.
*February 27, 2012*

**Physics 30**

First A(B-A) then subtract B again from that answer. I see A as (0,3.5) and B as (-4.2,0) I hope thats the right way algebraically.
*February 21, 2012*

**Physics 30**

Hi Bob ... the first post is actually the question .. subtract B from A(B-A)
*February 21, 2012*

**Physics 30**

Vectors A) 3.5 cm North B) 4.2 cm West Algebraically subtract B from A(B-A) Whaaaa? Please help
*February 21, 2012*

**math**

a sales representative earned four times as much in the fourth week of jan than any other week in jan what is the income for the fourth week
*February 19, 2012*

**math**

If a tree is 10 feet tall after two years and 25 feet tall after 5 years, find the rate of change of growth of the tree if y is the height in feet and x is the number of years. Be sure to give correct units.
*February 12, 2012*

**chemistry**

(100g)(.473J/g°C)(x-62°C) =-(500g)(4.184J/g°C)(x-22°C) Q = mass•specific heat•change in temperature Can someone show me how to solve this so i can teach myself before my test on Monday ..thanks for your time
*February 3, 2012*

**Math**

Fred runs a lap every 2 minutes and Mark runs a lap every 2.5 minutes. They start together. How long will it be before they are next to each other again?
*January 19, 2012*

**Trig**

(x+3)^2/4^2 + (y-2)^2/5^2 The location of the Foci are at: a.(-3,-1) and (-3,-5) b. (-3,2) and (-3,5) c. (-3,-3) and (-3,7) d. (-3,1) and (-3,-5) I get (-3,2) and (-3,5) Am I correct?
*January 14, 2012*

**Trig**

The question is: Set up a 2 column proof to show that each of the equations is an identity. Transform the left side to become the right side. a. (tan + cot)^2 = sec^2 + csc^2 I'm having trouble with this. b. (cos + sin)/cos + (cos - sin)/sin = csc sec I'm having ...
*January 8, 2012*

**Trig**

Thanks Damon.
*January 8, 2012*

**Trig**

The actual question goes : make the left the same as the right: left side: tan/sec - 1 = right side sin/1-cos
*January 8, 2012*

**Trig**

(sin/cos)/ ( 1/cos - 1) = I'm stumped
*January 8, 2012*