# Posts by bob

Total # Posts: 3,462

**Science**

A car's engine is only 12% efficient at converting chemical energy in gasoline into mechanical energy. If it takes 1.8 x 104 N of force to keep the car moving at a constant speed of 21 m/s, how much chemical energy would be needed to move the car a distance of 450 m at ...

**Physics**

A 4.0 x 101 kg wind sled is gliding East across a frozen lake at a constant speed of 12 m/s, when a gust of wind from the southwest exerts a constant force of 1.0 x 102 N on its sails for 3.0 s. With what velocity will the sled be moving after the wind has subsided?

**Physics**

A rock climber of mass 55 kg is hanging suspended from a rope tied to another climber of mass 65 kg on a horizontal cliff ledge. If the coefficient of kinetic friction between the climber on the ledge and the ledge is 0.45, what is the net acceleration of the climber on the ...

**Calculus**

i feel like you solved for when the stadium holds 59000 not 53000 like in his question hahaha WHICH IS PERFECT BECAUSE MY PROBLEM IS WITH 59000! yay :)

**Computers**

We are not here to do your homework for you, just to help.

**Math**

1/5

**Grammar**

Thanks Ms. Sue! I'm just going to continue to use it so no one will be confused. I must ask, since I've used this site for years and love it, how did you come about to working here? Or is this all volunteer work? I see you, Dr. Bob, and some other people haven't ...

**Grammar**

Lately when I've been reading news articles and website blogs, I've been seeing some funny grammar that I don't remember learning about. It deals with commas for a list of items. Normally I thought you would write like this: I have potatoes, carrots, and squash ...

**Trig**

find all solutions to the equation √3 csc(2theta)=-2 Would the answer be π/6 + 2πn, 5π/6 +2πn or π/6 + πn, 5π/6 +πn? or neither?

**math**

What annual interest rate was charged on a 2-year loan of $6300 if the simple interest paid was $1039.50? Show your work

**American History**

Examine the effects of World War II on the American family

**Math**

Webster Aquatic Center offers various levels of swimming lessons year-round. The March 2005 Monday and Wednesday evening lessons included instructions from Water Babies through Adults. The number in each classification is given in the table that follows. Swim Lesson Types No. ...

**Trig**

From a point P on level ground, the angle of elevation of the top of a tower is 27°10'. From a point 23.0 meters closer to the tower and on the same line with P and the base of the tower, the angle of elevation of the top is 51°30'. Approximate the height of ...

**U.S. GOVERNMENT**

A A

**algebra**

the senior class at highschool a and highschool b planned separate trips to the local amusement park the senior class at highschool a rented and filled 5 vans and 8 buses with 357 students highschoolb rented and filled 10 vans and 5 buses with 285 students every van had the ...

**STATS**

84

**english**

how do i write a thesis

**math**

what is 984 times 4 squared?

**chemistry**

is scraping of cheek cells an effective way to find if you have lung cancer?

**science - chemistry**

How much limestone will you need to neutralize lakes, using Snells law formula, and how would you draw that out?

**Fluid Mechanics**

Water enters a turbo-machine at a velocity 12 ft/s. The flow occurs in the horizontal plane. The inside diameters of the inlet and exit pipes are 1 ft and 2 ft, and the gage pressures at the inlet and exit are 10 psi and 5 psi, respectively. The machine is anchored at the ...

**Fluid Mechanics**

The gate OAB under water is 5 m-wide and is hinged along O as shown. (a) Find the hydrostatic force on the horizontal surface AB. (b) Determine the magnitude and point of action of the hydrostatic resultant force on the vertical surface OA. (c) Draw a free body diagram of the ...

**Fluid Mechanics**

Water at 600F flows steadily through a horizontal circular divergent duct and discharges into the atmosphere as shown. A manometer with a fluid of SG=2.0 is placed between the two cross-sections with diameters D1 = 0.5 ft and D2 = 0.7 ft. Assuming inviscid flow, determine: (a...

**Fluid Mechanics**

The components and their dimensions of a hydraulic jack are shown in the figure. The specific gravity of the fluid in the jack is SG=0.8. A force F=400 N is applied at the left end of the handle, which is hinged at the right end. Determine: (a) The fluid pressure p1 on the ...

**physics**

When chasing a hare along a flat stretch of ground, a greyhound leaps into the air at a speed of 10.2 m/s, at an angle of 16.3° above the horizontal. (a) What is the range of his leap? (b) For how much time is he in the air?

**Physics**

The Builder

**Physics**

At what angle to the surface must a submerged diver in a lake look toward the surface to see the setting sun just along the horizon?

**Physics**

A crown glass plate 2.5 cm thick is placed over a newspaper. How far beneath the top surface of the plate would the print appear to be if you were looking almost vertically downward through the plate?

**Physics**

A person lying at poolside looks over the edge of the pool and sees a bottle cap on the bottom, directly below. If the depth of the pool is 3.2 m, how far below the water surface does the bottle cap appear to be?

**statistics**

25

**Physics**

A man who is 6 ft tall is standing in front of a plane mirror that is 2 ft in length. If the mirror is placed lengthwise with its bottom edge 4 ft above the floor on a wall that is 5 ft away, how much of his image (i.e. what length of himself) can the man see? (Assume that his...

**Physics**

A man who is 6 ft tall is standing in front of a plane mirror that is 2 ft in length. If the mirror is placed lengthwise with its bottom edge 4 ft above the floor on a wall that is 5 ft away, how much of his image (i.e. what length of himself) can the man see? (Assume that his...

**Physics**

A man who is 6 ft tall is standing in front of a plane mirror that is 2 ft in length. If the mirror is placed lengthwise with its bottom edge 4 ft above the floor on a wall that is 5 ft away, how much of his image (i.e. what length of himself) can the man see? (Assume that his...

**Physics**

A man who is 6 ft tall is standing in front of a plane mirror that is 2 ft in length. If the mirror is placed lengthwise with its bottom edge 4 ft above the floor on a wall that is 5 ft away, how much of his image (i.e. what length of himself) can the man see? (Assume that his...

**Physics**

Standing 2.5 m in front of a plane mirror with your camera, you decide to take a picture of yourself without turning the camera around. To what distance should the camera be focused to get a sharp image?

**Physics**

A dog is sitting in front of a plane mirror. At a command it jumps at the mirror with a speed of 0.50 m/s. How fast does the dog approach its image?

**math**

At his school’s field day, 7 of Jake’s classmates won a bronze trophy, 14 won a silver trophy, and 10 won a gold trophy. If you choose one trophy winner at random, what is the probability that you would choose someone who won a bronze trophy?

**Physics**

You are heating water in a pot on the stove. Shortly before the water boils properly, bubbles of steam begin rising from the bottom of the pot but vanish before they reach the water’s surface. What happened to those bubbles?

**Physics**

At a restaurant, your glass of water contains 25% ice while your friend’s glass of water contains 75% ice. What can you say about their temperatures? Explain your answer

**chemistry**

haallllp me

**Physics**

You are heating water in a pot on the stove. Shortly before the water boils properly, bubbles of steam begin rising from the bottom of the pot but vanish before they reach the water’s surface. What happened to those bubbles?

**Physics**

At a restaurant, your glass of water contains 25% ice while your friend’s glass of water contains 75% ice. What can you say about their temperatures? Explain your answer.

**math**

p p

**Physics**

A thermoelectric-based power meter has a response time of 20 s and sensitivity (output voltage per unit incident power) of 90 mV/W. If the time response is reduced to 8 s by increasing the thermal conductance between the sensor element and heat sink, what will be the new ...

**Physics**

When you take a bath, how many kg of hot water (49 C) must you mix with cold water (13 C) so that the temperature of the bath is 36 C? The total mass of the water (hot and cold) is 191 kg.

**Physics**

At a birthday party, a student ate a piece of cake (food energy value of 400 calories). To prevent this energy from being stored as fat, she decides to drink ice water at 0 C. She reasons that the ingested ice water will be warmed up to her normal body temperature of 37 C and ...

**Physics**

How many Joules of thermal energy must be added to 5 kg of water at 20 C to bring it to the boiling point (at 100 C)?

**Physics**

A 0.2 kg glass cup at 20 C is filled with 0.4 kg of hot water at 70 C. Neglecting any heat losses to the environment, what is the equilibrium temperature?

**physics**

.04

**Algebra 2**

Combine The Rational Expressions and Simplify (3x-7)/(x^2-12x+27)-(3x-8)/(x^2-9x+18)+(x+2)/(x^2-15x+54)

**Geometry**

Find the arc length, of a 130 degree arc, in a circle with a diameter of 7.2 inches. Round your answer to the nearest thousandth

**Chemistry**

If a gas has a volume of 500 ml and pressure of 1.5 atm, what will the pressure be if the volume is reduced to 250 ml?

**english**

or parental love?

**english**

thank you sir, according to my reading, i reckon it's forgiveness as the father forgives his son for wasting the money?

**english**

okay it's obstacles. thank you. What is the main idea of “The Parable of the Prodigal Son”? a. sibling rivalry b. selfishness c. forgiveness d. parental love

**english**

listen i really need your help. I have to get these questions right or i wont be able to graduate so id really appreciate it if you could answer it. It would mean alot

**english**

a. statues b. obstacles c. arguments d. violations

**english**

Which word is closest in meaning to “impediments”?

**Information Systems in Organizations**

C C C D B

**social studies 9**

Dickens is famous for the names he gave to his characters-- Uriaha heap, mr gradgrind and little doritt are a few examples. often theses names help us ...

**Physics**

Suppose you are getting ready to take a nap, and you have a choice of lying stretched out on your back on a) a bed of nails, b) a hardwood floor, or c) a couch. Which one would you choose for the most comfort, and WHY?

**Physics**

Your right rear tire has to support a weight of 3000 Newtons. Normally the contact area of your tire with the road is 200 square centimeters. If the pressure in your tire is suddenly reduced from 32 pounds per square inch to 16 pounds per square inch, what must be the new ...

**Physics**

Two identical objects, one moving twice as fast as the other, collide with each other in the following way: 0--------> 2v v <----0 m m If the two objects stick together after the collision, will they be moving to the right, to the left, or not at all? Explain your answer.

**Math**

what am i doing i here i thought i was playing a video game!!!!!!!!!!!!

**algebra 2**

solve using substitution x^+y^-100=0 x+y-14=0

**Physics**

A physics textbook is launched up a rough incline with a kinetic energy of 200 joules. When the book comes momentarily to rest near the top of the incline, it has only gained 180 joules of gravitational potential energy. About how much kinetic energy will it have when it ...

**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