# Posts by bob

Total # Posts: 3,272

Physics
A 1200-kg frictionless roller coaster starts from rest at a height of 24 m. What is its kinetic energy when it goes over a spot that is 12 m high?

Physics
You are driving your race car around a circular test track. Which would have a greater effect on the magnitude of your acceleration, doubling your speed or moving to a track with half the radius? Why?

wolrd

Physics
An Indy car with a speed of 120 km/h goes around a level, circular track with a radius of 1 km. What is the centripetal acceleration of the car (in m/s/s)?

Physics
An object is executing circular orbits of radius 0.5 m. If it completes an orbit every 3 seconds, what is its tangential speed?

Math
How to rewrite an expression with negative exponents such as : -12(3x-1)^-5 *(6x+7)^5 + 30(3x-1)^-4 *(6x+7)^4 common factor is 6 but what can I pull out from the (3x-1)^-5 and (3x-1)^-4 ?

Chemistry
what is it supposed to be?

Chemistry
i got it wrong... i got 1.22x10^-32. help!

Chemistry
The pressure of a gas is 35 atmospheres at a temperature of 48 (degrees) C with constant volume. What will the new pressure be if the temperature is increased to 36 (degrees) C?

Physics!!
The universal gravitational con- stant is 6.672 × 10−11 N m2/kg2. Objects with masses of 152 kg and 269 kg are separated by 0.45 m. A 53.5 kg mass is placed midway between them. Find the magnitude of the net gravitational force exerted by the larger masses on the ...

PHysics!!
Starting from rest at a height equal to the radius of the circular track, a block of mass 25 kg slides down a quarter circular track under the influence of gravity with friction present (of coefficient μ). The radius of the track is 15 m. The acceleration of gravity is 9....

Physics!!
A cart loaded with bricks has a total mass of 25.2 kg and is pulled at constant speed by a rope. The rope is inclined at 21.6 ◦ above the horizontal and the cart moves 13.7 m on a horizontal floor. The coefficient of kinetic friction between ground and cart is 0.4 . The ...

Health
11 letter word beginning with e for the process which alcohol leaves the body?

chemistry
Write the equation for the decomposition of HI, knowing that the reaction requires 9.4 kj/mol of hydrogen forming. If 100.0 kj of energy are added, how many grams of iodine will form.

Physics 121
Two block are connected by a rope that runs over a pulley. The block on the tables has mass 4kg, the hanging block has mass 2kg, and the pulley has mass 0.5kg and radius 0.25m. Assume that the table is friction-less. If the block are released from the rest, determine their ...

science
171.5 m/s

physics
A 10.67 kg bowling ball has speed 4.35 m/s before hitting the floor. A(n) 66.5 g golf ball flies at much higher speed, so the two balls have exactly same kinetic energy. What is the speed of the golf ball? Note: neglect rotation of either ball. Answer in units of m/s.

Physics
Given: The universal gravitational con- stant is 6.672 × 10−11 N m2/kg2. Objects with masses of 152 kg and 269 kg are separated by 0.45 m. A 53.5 kg mass is placed midway between them. Find the magnitude of the net gravitational force exerted by the larger masses ...

physics
A 10.67 kg bowling ball has speed 4.35 m/s before hitting the floor. A(n) 66.5 g golf ball flies at much higher speed, so the two balls have exactly same kinetic energy. What is the speed of the golf ball? Note: neglect rotation of either ball. Answer in units of m/s.

Physics
Given: The universal gravitational con- stant is 6.672 × 10−11 N m2/kg2. Objects with masses of 152 kg and 269 kg are separated by 0.45 m. A 53.5 kg mass is placed midway between them. Find the magnitude of the net gravitational force exerted by the larger masses ...

Physics
Given: The universal gravitational con- stant is 6.672 × 10−11 N m2/kg2. Objects with masses of 152 kg and 269 kg are separated by 0.45 m. A 53.5 kg mass is placed midway between them. Find the magnitude of the net gravitational force exerted by the larger masses ...

Physics
A ball is rolled off the flat roof of a 15-storey building that is 45 m above a playground. When will the ball strike the ground if you can ignore air resistance? If you believe that there is not enough information given, explain what is needed.

Physics
I would say they hit the ground at the same time but im not sure

Physics
Two identical balls roll off the edge of a horizontal table top. One leaves traveling at twice the speed of the other. Which ball hits the floor first? Why?

Physics
A baseball is hit with a horizontal speed of 22 m/s and a vertical speed of 14 m/s upward. What are these speeds 1 s later?

Physics
I would say the true mass is 60 kg and that's as far as i got

Physics
You stand on a bathroom scale that rests on the floor of an elevator. Standing on the scale compresses internal springs and activates a dial that indicates your weight in newtons. When the elevator is at rest, the scale reads 600 N. Then the elevator begins to move upward with...

math
Express the infinite series below using sigma notation and then find the sum. 64 + 40 + 25 + 15.625... Any explanation would be excellent. Thank you so much.

Physics
Tom Brady (the Patriots’ quarterback) throws a football – at a speed of 30 mph at an angle of 50 degrees to the horizontal – toward an intended receiver 20 yd straight downfield behind the goal-line. The pass is released 7.5 ft above the ground. Assume that the ...

Physics
A juggler has a set of balls that she can toss into the air. If it takes her 0.2 s to transfer a ball from the receiving hand to the launch hand and she is able to throw a given ball straight up with a maximum speed of 10 m/s how many balls can she successfully juggle at any ...

Physics
Thanks a lot Elena

Physics
Two friends are at the local high school track, a circle measuring 440 yards for one complete lap. Abe can jog at 8.2 miles per hour while Bob’s jogging speed is 4.6 miles per hour. If they both start at the same point and jog in the same direction (say clockwise), how ...

Marketing
What is the preparation of reports for each level of responsibility in the company’s organization chart called?

Marketing
Managerial accounting is

math
12

Math
Mr. Rainier's car uses about 1.6 fluid ounces of gas per minute when the engine is idling. One night, he parked his car but forgot to turn off the motor. He had just filled his tank. His tank holds 12 gallons. About how many hours will it take before his car runs out of gas?

chemistry
YES! it was the OH^- that messed up my calculation. The answer you provided me was correct, thanks for all the help!

chemistry
for the %protonation = [(OH^-)/(BN)]*100 i tried doing 1.15*10^-3 / 0.39 * 100 = .295, but the answer is incorrect. can you tell me what i did wrong?

chemistry
nvm, it IS right, ty xD

chemistry
-log ka=8.52 ka= 3*10^-09 Kb= kw/ka = 10^-14/ 3*10^-09 = 3.4 *10^-06 kb= x^2/0.39 x= squre root of ( 3.4*10^-6*0.39) =1.15*10^-3 POH= -log[OH-]= -logx= -log 1.15*10^-3 =2.939 PH= 14 - 2.939 =11.06 IS THIS RIGHT?

chemistry
Calculate the pH and percentage protonation of the solute in an aqueous solution of 0.39 M quinine if the pKa of its conjugate acid is 8.52.

english
Durig literacy analysis, the writer reads a work and then

math
i don't know

math
tom had 8 pieces of pizza, tom ate one. How much is left

Thanks that seems to have worked the back of my text book says it is 2.1 but i got 2.5 close enough.

jackie mows a stip of uniform width around her 25m by 15m rectangular lawn and leaves a patch of lawn that is 60% of the original area. What is the width of the strip?

Networking
In your browser, you enter the URL of a website you use daily. After some delay, you receive a DNS error message that the host does not exist. a) What may have happened? Explain your reasoning. b) How would you logically disconfirm or test each possibility?

Networking
Assume that an average SNMP response message is 100 bytes long. Assume that a manager sends 40 SNMP Get commands each second. What percentage of a 128 kbps WAN link would the response message represent?

math
20.58

history
what event caused the greek city- states to put aside their differences.

physics
Two waves traveling on a string in the same direction both have a frequency of 100 Hz, a wavelength of 2cm and an amplitude of .02 m. What is the amplitude of the resultant wave if the original waves differ in phase (a) by Pi/6 and (b) by Pi/3

chem
Hey could you please help me. Why would K2CO3 be a better drying agent than Na2SO4 when drying out water from clohexanol?

Math
what is the median of the numbers 3,6,10,12,27,62

physics energy
A potential function is given by U(x) = 18 x^2. What will be the acceleration (in meters/second ^2) of a 8.00 kg mass, when it is at the position x = 0.500 m?

chemistry
What is the limiting reactant of 4000 grams of heptane is combusted with 7000 grams of oxygen?

Pre-calculus
Use the remainder theorem to find which of the following is not a factor of x3 + 12x2 + 47x + 60 the answer is x-5 but idk why

trig
simplify cox^2x-cos^4x

Chemistry
? lost- what chart?

Chemistry 2
(.032^2)x(.016^-1)^2 =4

Chemistry 2
i still don't get this

Mechanics for A-level
An object of mass 50kg rests on a rough plane inclined at an angle z to the horizontal. It is supported in this position by a light string parallel to the plane which is attached to the object and fixed to a point at the top of the plane. The string has a breaking strain of ...

finite math
Determine whether each system of linear equations has a)one and only one solution, b)infinitely many solutions, or c) no solution 2x-4y=5 3x +2y=6

physics
A uniform horizontal wire with a linear mass density of 0.48 g/m carries a 1.9 A current. It is placed in a constant magnetic field, with a strength of 3.5 10-3 T, that is horizontal and perpendicular to the wire. Neglect the magnetic field of the Earth. (a) As the wire moves ...

Call the length of string below point B as h, then diagonal of triangle = a - h. angle to vertical of string = theta T + Tcostheta = W use pythagoras to find h (a - h)^2 = b^2 + h^2 so h = (a^2 - b^2)/2a and costheta = h/(a-h) = (a^2 - b^2) /(2a(a - [(a^2 - b^2)/2a] ) which ...

physics
A +5.7C X 10 to the -6 power point charge is on the x-axis at x=-3.0m,and a +2.0C X 10 to the -6 power point charge is on the x-axis at x=+1.0m.Determine the net electric field (magnitude and direction) on the y-axis at y=+2.0m.

Government
The Anti-federalists were against ratification of the constitution mostly because

science
Examine the obvious environmental impacts as well as significant social and physical ramifications of urban sprawl. What is the relationship between landscape and psychological well being? After defining this relationship, discuss how the presence or absence of natural beauty ...

science
Give examples of how humans have increased their food supply and what effects these methods have on the environment overall.

chemistry
how does the addition of a nonvolatile solute affect the vapor pressure of the solvent into which it is dissolved?

chemistry
2- A 0.310 M solution of a weak acid, HX, has a pH of 2.53 a. Find the [H+] and the percent ionization of nitrous acid in this solution. b. Write the equilibrium expression and calculate the value of Ka for the weak acid. c. Calculate the pH of the solution formed by adding 10...

chemistry
thank you!

Chemistry
need more help

Chemistry
need more help

math
The space station is going 17500 mph as it orbits the earth. How long will it take to orbit 1 time if the earths diameter is 7926 miles and the space station orbits at 240 miles above the earth.

Science
How many milliliters of water at 20.0 °C are formed in the combustion of 25.0 g of a methanol–propanol mixture that is 62.5% methanol by mass? Assume there is an excess of oxygen available.

chemistry
120.g NO

chemistry
How man grams of nitrogen monoxide are needed to react with adequate oxygen to produce 89.6 L of nitrogen dioxide

Chemistry
100 J

The diagram shows a cylinder of mass 20 kg lying at rest on two smooth planes inclined at angles of 40 degree and 50 degree to the horizontal. Calculate the reaction force exerted by the planes on the cylinder. For digram, please click the following link

chemistry
If HClO2 is a stronger acid than HF, which is stronger than HOCl, then the order of strengths of the conjugate bases of these acids is ______ < _____ < _____ a) ClO- < F- < ClO2- b) ClO2- < ClO- < F- e) F- < ClO2- < ClO- c) ClO- < ClO2- < F- d) ...

chemistry
The Ka for HOBr is 2.4 x 10-9. Thus, you can report the pKb for OBr– as a) 4.2 x 10-6 b) 9.62 c) 5.38 d) 8.62 e) 1.38 help!

chemistry
Which salt below will dissolve in water to yield an acidic solution? a) NaNO2 b) K C§¤O4 c) NH4NO3 d) Na2CO3 e) Mg Br2 help!

chemistry
The approximate pH of a 3.0 x 10-3 M solution of the strong acid H2SO4 is a) 3.5 b) 3.0 c) 2.5 d) 2.2 e) -3.0 how do you do this?

chemistry
The ion HPO4–2 has both a conjugate base as well as a conjugate acid. The conjugate base of this ion is (1) while the conjugate acid is (2). a) (1) = H2PO4– (2) H3PO4 b) (1) = PO4– (2) H2PO4+ c) (1) = PO4–3 (2) H2PO4– d) (1) = HPO5–3 (2) HPO3–...

chemistry
Which of the following is a Bronsted-Lowry base but not a Lewis base? a) H2O c) CN– e) all choices are both a B/L and Lewis base. b) CO3–2 d) NH3 need help deciding

chemistry
Which of the following is not amphiprotic? a)H2O c)NH4+ e)all choices are amphiprotic b)HSO4 – d)H2PO4– need help!

english
In The Secret, the secret is found in a a conversation. b letter. c line of poetry. d newspaper column. I think a

chemistry
Using this data, 2 NO(g) + Cl2(g) == 2 NOCl(g) Kc = 3.20 X 10-3 NO2(g) == NO(g) + ½ O2(g) Kc = 3.93 calculate a value for Kc for the reaction, NOCl (g) + ½ O2 (g) == NO2 (g) + ½ Cl2 (g) A. 20.2 B. 2.06 X 10-4 C. 4.49 D. 4.84 X 10-3 E. 0.223 eliminated down...

chemistry
Using this data, 2 NO(g) + Cl2(g) == 2 NOCl(g) Kc = 3.20 X 10-3 NO2(g) == NO(g) + ½ O2(g) Kc = 3.93 calculate a value for Kc for the reaction, NOCl (g) + ½ O2 (g) == NO2 (g) + ½ Cl2 (g) A. 20.2 B. 2.06 X 10-4 C. 4.49 D. 4.84 X 10-3 E. 0.223 eliminated down...

physics
A child moves with a speed of 5.40 m/s when positioned 14.0 m from the center of a merry-go-round. Calculate the net force (in newtons) exerted on the child, whose mass is 26.0 kg.

chemistry
when you reverse it do you get a negative?

chemistry
Using this data, 2 NO(g) + Cl2(g) == 2 NOCl(g) Kc = 3.20 X 10-3 NO2(g) == NO(g) + ½ O2(g) Kc = 3.93 calculate a value for Kc for the reaction, NOCl (g) + ½ O2 (g) == NO2 (g) + ½ Cl2 (g) A. 20.2 B. 2.06 X 10-4 C. 4.49 D. 4.84 X 10-3 E. 0.223 eliminated down...

Math
A bag has 4 red, 6 white, and 9 blue marbles. How many ways can 5 marbles be selected if 2 are one color, and 3 are another color?

PHi103
The truth table for a valid deductive argument will show

math
(4.35E-2 - x)(7.56E-2 -x ) ============================ (0.324 + 2x)2 Rearrange to get an expression of the form ax2 + bx + c = 0 and use the quadratic formula (solve for x. This gives: x = 1.05E-2, 0.143 basically i understand they use the quadratic equation but how did they...

english 11
just took it. Joyce has the right answers.

english 11
a b c d

physics
a 25000000 gr rocket is propelled from rest by an engine that produces a 312500 kgm/s2 for 1.375s A) What is the sleds acceleration? B) What is the velocity after 1.375s?

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