# 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?

**international trade**

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

**Grade 11 Math**

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

**Grade 11 Math**

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 ...

**Mechanics (A level), Please help**

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

**AQA Mechanics (M1), Statics and forces,please help**

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...

**chemistry this is confusing to me please help**

Screw u

**chemistry this is confusing to me please help**

HAHA no

**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?