Thursday

February 26, 2015

February 26, 2015

Total # Posts: 36

**Chemistry**

how do you convert mg to moles?
*January 19, 2013*

**Chemistry**

The dissolved Ca++ concentration in a river is approximately 30 mg/L. This concentration is equivalent to ___ ppm or ___ mol/L, or ___ cmol/L. It would provide ___ cmolc+/L. (c+ is a subscript)
*January 19, 2013*

**math - please help**

What is the rotational speed (rpm) of the 64 in diameter rear tires of a tractor traveling at 6.5 mph if there is no slippage? How do I work this? Thank you.
*March 31, 2012*

**math**

Estimate the gallons of paint needed to cover the outside of a cylindrical silo which is 30 feet in diameter and 70 feet high. Do not include any roof area. The paint covers approximately 150 square feet/gallon.
*March 30, 2012*

**math **

convert: 6000 kg to ___ tonnes (metric tons) 6000 kg to ___tons 1 acre-ft of water to ___gallons 32 psi to ___kpa 10 psfito ___ oz/in^2
*March 28, 2012*

**physics - please help**

I forgot to mention that I got 6.417E29 for part A and 2.688E34 for part B. Both answers were wrong. Please help. Thank you.
*March 3, 2012*

**physics - please help**

Assume the earth is a uniform sphere and that its path around the sun is curcular. Calculate the kinetic energy that the earth has because of its rotation about its own axis. For comparison, the total energy used in the US in one year is about 9.33 x 10^9 J b) Calculate the ...
*March 3, 2012*

**Physics - still confused -Please help**

In 9.7 s a fisherman winds 2.1 m of fishing line onto a reel whose radius is 30 cm (assumed to be constant as an approximation). The line is reeled in at constant speed. Determine the angular speed of the reel in rad/s. Thank you.
*February 25, 2012*

**Physics Please help**

I'm still confused. to find angular speed = tnngenital speed/radius, would the radii cancel out, leaving only the tangential speed? still confused as to set up
*February 25, 2012*

**Physics**

In 9.7 s a fisherman winds 2.1 m of fishing line onto a reel whose radius is 30 cm (assumed to be constant as an approximation). The line is reeled in at constant speed. Determine the angular speed of the reel in rad/s. Thank you.
*February 25, 2012*

**Physics**

A box is being with a velocity v by a force P (parallel to to v) along a level horizontal floor. the normal force is Fn, the kinetic frictional force if fk, and the weight of the box is mg. Decide which forces do positive, zero or negative work and why?
*February 12, 2012*

**Physics - position time graph**

The graph shows position as a function of time for 2 trains running on parallel tracks. The graph shows line A at a 45 degree angle,beginning at origin. Curve B also begins at origin, continues up and to the right (all in quadrant 1, like a sq root function) It crosses Line A ...
*January 29, 2012*

**Physics**

Two forces, F1 and F2, act on the 5.00 kg block shown in the drawing. The magnitudes of the forces are F1 = 69.0 N and F2 = 24.5 N. What is the horizontal acceleration (magnitude and direction) of the block? F1 is pointing at the top left corner of the box forming a 65 degree...
*January 21, 2012*

**Physics Please Help**

Force 1 is pushing on the top left corner of the box. The arrow forms a 65 degree angle with the verticle (as if the box were extended straight left, from 9:00 to the arrow = 65 degrees) I found F1 horizontal component to be 69 cos 65 = 29.16 N F2 is pushing to the left. F2 = ...
*January 21, 2012*

**Physics Please Help**

Two forces, F1 and F2, act on the 5.00 kg block shown in the drawing. The magnitudes of the forces are F1 = 69.0 N and F2 = 24.5 N. What is the horizontal acceleration (magnitude and direction) of the block? F1 is pointing at the top left corner of the box forming a 65 degree ...
*January 21, 2012*

**algebra - exponentials**

My question is how do I know that N increases by a factor of 2.9 each day. (see below) Let N(t) be number of bacteria after t days. N(t) = Pa^t for some constants P and a. N(2) = 5400 and N(6)=382,000. a)before working problem, estimate value of N(5). b) write down 2 equations...
*November 6, 2011*

**algebra - please help**

Let N(t) be number of bacteria after t days. N(t) = Pa^t for some constants P and a. N(2) = 5400 and N(6)=382,000. a)before working problem, estimate value of N(5). b) write down 2 equations for P and a, one when t=2 and one when t=6, and use these two equations to compute a ...
*November 5, 2011*

**math**

If log (base b) 3 = 1.099 and log (base b) 6 = 1.792, find log (base b) 18 = ???
*November 5, 2011*

**algebra**

I won't have access to this on a test. How can I work it on a calculator.
*October 15, 2011*

**algebra**

Find all positive solutions to: x^6 + 7x = 4x^4 - x^2 + 8
*October 15, 2011*

**algebra**

height of a projectile thrown straight up from top of 480 ft hill t seconds after bing thrown up with initial velocity vo ft/s is h = -16t^2 +vot + 480 If vo = 96, find times when the projectile will be at a) height of 592 ft above the ground and b) crash on the ground.
*October 10, 2011*

**algebra - Please help**

Use the equation y = ax^2 + bx + c where x is the horizontal distance a baseball has traveled and y is the height of the ball at the given distance. 1)Are some values of y unreasonable? 2)How is this information important for choosing a window for the graph? 3) With respect to...
*October 7, 2011*

**algebra**

Use the equation y = ax^2 + bx + c where x is the horizontal distance a baseball has traveled and y is the height of the ball at the given distance. 1)Are some values of y unreasonable? 2)How is this information important for choosing a window for the graph? 3) With respect to...
*October 6, 2011*

**Algebra**

Produce a third degree polynomial that has exactly the roots -3 and 5 with y-intercept 1350. I understand I could start with (x+3)(x-5)^2, but i don't know how to get the y-intercept 1350 with the same conditions. Please help. thank you.
*October 4, 2011*

**Math **

Produce a third degree polynomial that has exactly the roots -3 and 5 with y-intercept 1350. I understand I could start with (x+3)(x-5)^2, but i don't know how to get the y-intercept 1350 with the same conditions. Please help. thank you.
*October 3, 2011*

**physics - need help**

Resistors of 30 ohms and 60 ohms are connected in parallel and joined in series to a 10 ohm resistor. The circuit voltage is 180 volts. Find: the voltage of the parallel circuit the voltage across the parallel circuit the current through the 10 ohm resistor
*May 18, 2011*

**Physics**

what current will flow through a resistance of 11 ohms when the emf impressed acrosss the resistance is 2.8 volts?
*May 17, 2011*

**science**

Thank you
*May 17, 2011*

**science**

If an ammeter records 8 amperes and a voltmeter records 1.1 volts, the resistance of the conductor in the circuit is ___ ohms
*May 17, 2011*

**physics**

If an auto weighing 13,345 N causes a bridge to sag 0.0254 m, a truck weighing 26,690 N would cause the bridge to sag how many meters, assuming the truck was on the same spot as the auto had been? How do I even set this up?
*March 16, 2011*

**physics**

So F = 22500 Am I right in thinking it is POSITIVE?
*February 20, 2011*

**physics**

a bullet with a mass of 5 g and a speed of 600 m/s penetrates a tree to a depth of 4 cm. Assume that a constant frictional force stops the bullet. Calculate the magnitude of this frictional force. I used KE = 1/2 mv^2 = 900 J then F (friction ) = W/d = 22500 N BUT I don't ...
*February 20, 2011*

**physics**

a bullet with a mass of 5 g and a speed of 600 m/s penetrates a tree to a depth of 4 cm. Assume that a constant frictional force stops the bullet. Calculate the magnitude of this frictional force. *Also, I'm not sure if the answer would be positive or negative.
*February 20, 2011*

**physics**

a spring with spring constant of 30 N/m is stretched 0.2 m from its equilibrium position. How much work must be done tostretch it an additional 0.1 m?
*February 19, 2011*

**physics**

the kilowatt-hour is a unit of: force, work, power, or time?
*February 19, 2011*

**physics**

a 2575 kg van runs into the back of a 825 kg compact car at rest. They move off together at 8.5 m/s. Assuming no friction with the ground, find the initial speed of the van.
*February 7, 2011*

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