# Posts by Dan

Total # Posts: 1,188

**Physics**

Train A starts at 4 miles South of a bridge and heads North at a constant speed of 30 miles per hour. Train B starts 6 miles North of the bridge. a. What velocity must Train B have so that the two trains cross the bridge at the same time? b. If Train B goes at 35 miles per ...

**Physics**

A train is moving towards a destroyed bridge. The velocity of the train remains constant at 20 m/s. A person inside the train realizes that they will die unless they run to the back of the train and jump out. If the person is 15 m from the back of the train and the back of the...

**Physics**

At a certain instant, a ball is thrown downward with a velocity of 8.0 m/s from a height of 40 m. At the same instant, another ball is thrown upward from ground level directly in line with the first ball with a velocity of 12 m/s. Find (a) the time when the balls collide and (...

**Physics**

A plane is flying at 25 degrees north of west at 190km/ h. Suddenly there is a wind from 15degrees north of east at 45 km/ hr. what is the planes new velocity with respect to ground in standard position

**Physics**

Plane flying southwest at 155mi/hr. their is a wind from the west at 45.0mi/hr. what's the planes new velocity

**MaTH**

so is the perpendicular line is -2/3? What is the parallel line?

**MaTH**

Consider the line 9x-6y=-3 . What is the slope of a line parallel to this line? What is the slope of a line perpendicular to this line?

**Mth**

I suck in math as you can see and yes I will love more help

**Math (Pre-Cal)**

There is exactly one triangle the length of whose sides are integers in arithmetic progression and whose area is 156 square units. Find the perimeter of this triangle.

**Math**

An airplane approaches a runway at a 3 degree angle of depresssion. If the plane is flying at 30,000 ft., find the ground distance from the airport to the point directly below the plane when the pilot begins the descent. Round your answer to the nearest foot.

**Math**

An airplane approaches a runway at a 3 degree angle of depresssion. If the plane is flying at 30,000 ft., find the ground distance from the airport to the point directly below the plane when the pilot begins the descent. Round your answer to the nearest foot.

**Biochemistry**

Do you add Nacl or HCL if your target buffer pH is 8, and the buffer is HEPES

**Physics**

Two forces are applied to a car in an effort to move it, as shown in the following figure, where F1 = 433 N and F2 = 354 N. (Assume up and to the right as positive directions.) F1 is 10 degrees west of the y axis, F2 is 30 degrees east of the y axis. (a)What is the direction &...

**Physics**

Forces of 11.3N north, 19.1N east, and 14.5N south are simultaneously applied to a 4.12kg mass as it rests on an air table. What is the magnitude of its acceleration? What is the direction of the acceleration in degrees? (Take east to be 0 degrees and counterclockwise to be ...

**Physics**

A rowboat crosses a river with a velocity of 3.30 mi/h at an angle 62.5° north of west relative to the water. The river is 0.795 mi wide and carries an eastward current of 1.25 mi/h. How far upstream is the boat when it reaches the opposite shore?

**MATH**

THREE QUARTERS OF A POUND OF HONEY COSTS $4 HOW MUCH HONEY WOULD YOU GET FOR $6

**Trigonometry**

cos 17pi/6 + tan 17pi/6

**Physics**

compare the collision of a baseball and bat with the collision of a baseball and a fielder's glove when the baseball is caught. During which collision is there a greater momentum change for the baseball?

**math**

what is 0.0678/100

**Physics**

Question: particle J with zero initial mass and X energy accelerates from a static start to 'C' (light speed) in a time frame of N and mass increases 10 to the 28th power per nanosecond- -What is the mass on particle J? -What is the energy of particle J?

**PLEASE HELP BIO**

If the side chain of a glutamic acid residue has a pKa of 4.1, at pH 6.1 the ratio of uncharged to charged side chain would be about A. 100:1 B. 10:1 C. 1:1 D. 1:10 E. 1:100 -i HAVE NO IDEA Which of the following amino acids has a side chain that can serve ONLY as a hydrogen ...

**biology**

If the side chain of a glutamic acid residue has a pKa of 4.1, at pH 6.1 the ratio of uncharged to charged side chain would be about A. 100:1 B. 10:1 C. 1:1 D. 1:10 E. 1:100

**biology**

Which of the following amino acids has the most hydrophilic side chain? A. F B. Q C. V D. M E. A

**biology**

Which of the following amino acids has a side chain that carries a negative charge in its conjugate base form? A. H B. W C. C D. K E. N

**physics**

The largest-caliber antiaircraft gun operated by the German air force during World War II was the 12.8 cm Flak 40. Suppose this weapon fired a 26.2 kg shell with a muzzle speed of 800 m/s. What propulsive force was necessary to attain the muzzle speed within the 6.00 m barrel...

**Physics**

Find the speed, v, of a pendulum at the bottom of its swing (B), given that it has mass m and initial height at A is h (the difference in height from B to A). Your answer will be in terms of g as well. Included is a drawing of a pendulum at its maximum height (A), and at its ...

**Linear Algebra**

Can you perform using matrix? Thank you very much

**Linear Algebra**

Consider the system x-2y=k-1 4x+(1-k^2)y=8 For what values of k does the system have a. unique solution? b. infinitely many solutions? c. no solution?

**math steve**

steve can you explain step by step please 8x=5y and 3y=14z then 12x= how many z's

**math**

if 8x=5y and 3y=14z then 12x= how many z's

**calculus**

A 100 inch piece of string is cut into 3 pieces. One piece forms a circle, one forms a square and 1 forms an equilateral triangle. If the perimeter of the triangle is equal in length to the perimeter of the square how long should each piece of string be to minimize the total ...

**math**

compare two cell phone companies and determine which is the better deal. Needs to be in a y=mx+b equation for each company. company a $40 base rate plus every minute costs .05 company b base rate $30 plus every minute costs .07 based on 800 minutes PLEASE HELP ME ASAP!

**Chemistry Help**

Write a balanced equation for the reaction between an aqueous solution of calcium nitrate being mixed with an aqueous solution of sodium phosphate Identify the precipitate.

**Finance**

Arena Distributors is a new company and currently pays no dividends. The company has just reported earnings of $1.5 per share and its earnings are expected to grow at a 15 percent annual rate over the next four years. Following this four-year high growth period earnings will ...

**Finance**

Seven years ago a semi-annual coupon bond with a 10% coupon rate, $1,000 face value and 15 years to maturity was issued by Corn Inc.. Teddy bought this bond two years ago when the market interest rate was 12%. And now the market interest rate is 5%. If teddy sells the bond now...

**math URGENT!!!!!!!!!!!!**

a 12x12-inch square is divided into n^2 congruent squares by equally spaced lines parallel to its sides. circles are inscribed in each of the squares. find the sum of the areas of the circles. answer and please explain step by step how u got the answer!! please!!!!

**com sci**

A rational number is the form of a/b, where a and b are integers with b != 0. Develop and test a class for processing rational numbers. The class should have a numerator data member and a denominator data member. It should read an display all rational numbers in the format a/b...

**physical**

to strengthen his arm and chest muscles, an 82-kg athlete who is 2.0 m tall is doing push ups. his center of mass is 1.15 m from the bottom of his feet, and the centers of his palms are 30.0cm from the top of his head. find the force that the floor exerts on each of is feet ...

**Physics**

Which one of the following stresses would be most likely to cause a bone to fracture? A) tensile stress B) compressive stress C) sheer stress D) bulk stress

**math URGENT!!!!!!!**

a rectangular sheet of paper is folded in half, with the crease parallel to the shorter edge. it happens that the ratio of longer side to shorter side remains unchanged. what is this ratio? answer this and explain how u got the answer.. PLEASE??!

**Computer Science**

Overview The purpose of the assignment is to develop a basic understanding and skills programming of input/output ports and device polling. The assignment examines hardware polled input from a push button. Assignment 1 The assignment is based on the flashing LED of the MSP430 ...

**math**

Alexa and Emma are looking up at their house from the backyard. From alexa's point of view, the top of the house is at an ang;e of elevation of 40 degree. From Emma's point of view, directly closer to the house, it is 60 degree. The house is 15 metres high. How far ...

**math URGENT!!!!**

please show how u got the answer

**math URGENT!!!!**

i have a list of 5 different numbers. the sum of 2 of the numbers is 0. the sum of 2 of the numbers is 1. the sum of 2 of the numbers is 2. the sum of 2 of the numbers is 3. the sum of 2 of the numbers is 4.the sum of 2 of the numbers is 5.the sum of 2 of the numbers is 6. the...

**math..reiny..help!!**

is that the area of big or small triangle?

**math URGENT!!!!**

the midpoints of the sides of a triangle are (1,1),(4,3),and (3,5). find the area of the triangle. please answer and show how u did it step by step please!!!! how do i find area of the smaller triangle?

**math URGENT!!**

so is that the area of big triangle or small?

**math URGENT!!**

how do i find the area of the little triangle? Reiny,

**math URGENT!!**

the midpoints of the sides of a triangle are (1,1),(4,3),and (3,5). find the area of the triangle. please answer and show how u did it step by step please!!!!

**Trig**

From a point 120 feet from the base of a plant building the angle of elevation to the roof line of the building is 38 degrees. The angle of elevation to the top of an antenna is 43 degrees. The antenna is attached to the nearest edge of the roof and the ground is flat. The ...

**mathURGENT!!!!**

the midpoints of the sides of a triangle are (1,1),(4,3),and (3,5). find the area of the triangle. what is the answer and can u explain how u got it step by step? please...

**math**

42 is evenly divisible by both 6 and 7

**math URGENT!!**

a rectangular box measures 4 by 5 by 2 meters. what is the length of the longest pole that can fit into the box?

**math**

how did u get that?

**math**

a rectangular box measures 4 by 5 by 2 meters. what is the length of the longest pole that can fit into the box?

**math**

amee, ben, carly, and darrien are friends. darrien has no money. amee gives darrien 1/4 of her money. ben gives darrien 1/5 of his money. carly gives darrien 1/3 of her money. each person gave darrien the same amount. what fraction of the groups total money does darrien have ...

**7th grade math**

b) 2 7/8 inches

**Science**

x = (v+u)(v-u)/2a where x = distance, v = final speed, u = initial speed, a = acceleration substituting known values: 130 = (30)*(-30)/2a a = -900/260 = -3.46 m/s^2 f = ma u(k)*f(normal) = m*a u(k)*m*g = m*a u(k) = a/g u(k) = 3.46/9.8 = 0.35

**Math does anyone know this?**

they are parallel....two nonvertical lines are parallel if their slopes are equal and have different y intercepts..

**math - still don't get it**

your welcome! anytime :)

**math - still don't get it**

because as long as the number(4) is right after the decimal point it doesnt matter how many 0's are in front of decimal or after the 4. think of it in dollar amount 0.4 is 0dollars and 40 cents. .40 is still 0 dollars and 40 cents thus 0.4=.40 if it were a different number...

**math**

its equal to...

**math**

can u explain that a little further steve?

**math**

describe the picture you would get by graphing the solutions(if there are any!) to the equation (x+y)^2=x^2+y^2

**math**

there are 15 boys and 18 girls in fifth grade. Find the ratio of boys to girls in fifth grade.(how do I get the answer) can someone show me how to work the problem

**Physics**

12 ft

**math**

is there an equation for this?

**math**

an object released from rest will fall 16t^2 feet, t seconds after it is dropped. 2 pebbles are dropped, one after the other, from a cliff that is 64 feet high. the 2nd pebble is released the instant the first pebble has fallen exactly one foot. how far above the ground is the...

**math**

consider the equation x^2+kx+1=0 a single fair die(dice)is rolled to determine the value of the middle coefficient, k. the value for k is the number of dots on the upper face of the die. what is the probability that the equation will have real, unequal roots?

**Physics**

A falling iPad takes 0.15 s to travel past a window 2.7 m tall. From what height above the top of the window did the mobile device fall? Equation to use?

**Physics**

A falling iPad takes 0.15 s to travel past a window 2.7 m tall. From what height above the top of the window did the mobile device fall? What equation would I use for this?

**trigonometry**

Suppose θ is an angle in standard position whose terminal side lies in Q II. If sin θ = 13 12 , find sec θ.

**physics**

An airplane flies 200 km due west from city A to city B and then 270 km in the direction of 31.0° north of west from city B to city C. (a) In straight-line distance, how far is city C from city A? (b) Relative to city A, in what direction is city C?

**physics**

An airplane flies 200 km due west from city A to city B and then 270 km in the direction of 31.0° north of west from city B to city C. (a) In straight-line distance, how far is city C from city A? (b) Relative to city A, in what direction is city C?

**physics**

A river flows due east at 2.00 m/s. A boat crosses the river from the south shore to the north shore by maintaining a constant velocity of 11.0 m/s due north relative to the water.

**Math**

1. b 2. c 3. c 4. a

**physics**

A 5.21 box sits on a ramp that is inclined at 37.8 above the horizontal. The coefficient of kinetic friction between the box and the ramp is 0.29. What horizontal force is required to move the box up the incline with a constant acceleration of 4.00 ?

**math**

malik paid 480$ to purchase a certain number of pizzas, but 2 extra were delivered which decreased the amount per pizza by 1$. how many pizzas were delivered?

**math**

Computers manufactured by a certain company have a serial number consisting of a letter of the alphabet followed by a five-digit number. If all the serial numbers of this type have been used, how many sets have already been manufactured?

**economics**

Say your parents give you a car for your birthday. It is not the new model you wanted, but it's in very good condition. They bought it used for $15,000 (market value). The cost of keeping the car to you is (not counting maintenance and operation cost) is:

**economics**

Say your parents give you a car for your birthday. It is not the new model you wanted, but it's in very good condition. They bought it used for $15,000 (market value). The cost of keeping the car to you is (not counting maintenance and operation cost) is:

**accounting**

A company purchased a machine on January 1 of the current year for $750,000. Calculate the annual depreciation expense for each year of the machine's life (estimated at 5 years or 20,000 hours, with a salvage value of $75,000). During the machine's 5-year life its ...

**health**

Thank you very much Ms.Sue really appreciate it:)

**health**

I mean you could just look at the answer choices in the asked question instead of making a "smart" dumb question. (not trying to be rude but its common sense)

**Physics**

When a resistor is connected across the terminals of an ac generator (112 V) that has a fixed frequency, there is a current of 0.500 A in the resistor. When an inductor is connected across the terminals of this same generator, there is a current of 0.400 A in the inductor. ...

**Physics**

When a resistor is connected across the terminals of an ac generator (112 V) that has a fixed frequency, there is a current of 0.500 A in the resistor. When an inductor is connected across the terminals of this same generator, there is a current of 0.400 A in the inductor. ...

**math**

Oops I was thinking of 8 times 9 It's 126

**math**

72

**math**

Planets A, B and C orbit a certain star once every 3, 7, and 18 months respectively. If the three planets are now in the same straight line, what is the smallest number of months that must pass before they line up again?

**PHY: To AJAYB, follow up on previous response**

First, I'd like to thank you for your response to my question. However, I had some follow up questions on your response from Saturday, July 28, 2012 at 8:27am. If you could take a look at that post and get back to me, it would be greatly appreciated.

**Physics- Repost (Answer did not make sense)**

Thanks for your response, but I have a few questions. For part B, why is full battery voltage 6V, and not 12V? For part C, my question is once again about using 6V in the calculation for finding q0, as well as units. Using 6V, qo= 54 uC? For the time constant, I plugged in ...

**Physics- Repost (Answer did not make sense)**

In the circuit below, at time t = 0, the switch is closed, causing the capacitors to charge. The voltage across the battery is 12 V The circuit: flickr. com/photos/ 68751220@N03 /6848519773/ A)Calculate the time constant for the RC circuit B)Calculate the time required for the...

**physics**

I plugged the #'s into that site you supplied, but I still get my answer of 0.012 seconds, not the 1.2E-5 seconds you put?

**physics**

I meant 0.012 sec for part A

**physics**

In the circuit below, at time t = 0, the switch is closed, causing the capacitors to charge. The voltage across the battery is 12 V The circuit: flickr. com/photos/ 68751220@N03 /6848519773/ A)Calculate the time constant for the RC circuit B)Calculate the time required for the...

**Physics**

The work done by an electric force in moving a charge from point A to point B is 3.75 x 10^-3 J. The electric potential difference between the two points is VA - VB = 54.6 V. What is the charge? Not sure if I did this correctly: I believe this is an equation: deltaV= (-Wab)/q ...

**physics**

An object carries a charge of -8.0 uC, while another carries a charge of -2.0 uC. How many electrons must be transferred from the first object to the second so that both objects have the same charge? Qavg = (object 1 + object 2)/2 Qavg= -5uC Object 2- Qavg = 3uC 3E-6 C/1.6E-19...

**Physics**

Those "i" things before the "C" were supposed to be micro for microcoulombs

**Physics**

An object carries a charge of -8.0 ìC, while another carries a charge of -2.0 ìC. How many electrons must be transferred from the first object to the second so that both objects have the same charge? Qavg = (object 1 + object 2)/2 Qavg= -5ìC Object 2- Qavg...

**chemistry 12**

hey i was wondering, i have this question: Sketch a pH curve for the titration of 40.00mL of 0.100 M hydrazine, H2NNH2, having a K of 3.0x10^-6 by 0.100 M HCIO4 i know you can t sketch but could you tell me what to do with the "K of 3.0x10^-6" i could sketch the ...