# Justin

Most popular questions and responses by Justin-
## Physics

Suppose you exert a force of 180 N tangential to a 0.280-m-radius 75.0-kg grindstone (a solid disk). (a)What torque is exerted? (b) What is the angular acceleration assuming negligible opposing friction? (c) What is the angular acceleration if there is an

*asked on July 14, 2013* -
## Geometry

Which of the following represents a chord but not a diameter of the circle? A. TR B. SN C. PM D. SM

*asked on January 20, 2017* -
## art

The math tessellations: unit 4 1. The architectural design was created by: 1. using an organic pattern in the form of tessellation. 2. using a geometric pattern in the form a tessellation. 3. using no definite pattern and placing shapes randomly. 4. using

*asked on October 21, 2016* -
## Physics

What is the moment of inertia of an object that rolls without slipping down a 2.00-m-high incline starting from rest, and has a final velocity of 6.00 m/s? Express the moment of inertia as a multiple of MR2, where M is the mass of the object and R is its

*asked on July 14, 2013* -
## Science

Explain what Maria and craters are and how they formed.

*asked on January 31, 2017* -
## Physics

The pressure exerted by a phonograph needle on a record is surprisingly large. If the equivalent of 1.00 g is supported by a needle, the tip of which is a circle 0.200 mm in radius, what pressure is exerted on the record in N/m2?

*asked on July 14, 2013* -
## Physics Prob.

A 22.0 kg child plays on a swing having support ropes that are 2.00 m long. A friend pulls her back until the ropes are 45.0 ∘ from the vertical and releases her from rest. What is the potential energy for the child just as she is released, compared with

*asked on November 24, 2017* -
## physics

A copper wire has a resistance of 0.425 at 20.0°C, and an iron wire has a resistance of 0.455 at the same temperature. At what temperature are their resistances equal?

*asked on September 15, 2013* -
## science

how many kilojoules of heat must be transferred to a 480 g aluminum pizza pan to raise its temperature from 22 degree c to 234 degree c? The specific heat of aluminum in this temperature range is 0.97 J/g degree C.

*asked on October 28, 2011* -
## economics

you find out that your aunt works for a defense manufacturing company that has several defense contracts with the government. she tells you that she works for a team that is producing a communications satelluite

*asked on January 21, 2014* -
## science

A science teacher tells her class that their final project requires the students to measure a specific variable and determine the velocity of a car with no more than 2.5% error. Jennifer and Johnny work hard and decide the velocity of the car is 34.87 m/s.

*asked on May 19, 2013* -
## Chemistry

1. State specifically how you would make a conclusive test for an iron (III) salt. 2. Which test for iron (II) ions is conclusive. 3. Suppose you have a solution containing both an iron (II) salt and an iron (III) salt. How would you proceed to identify

*asked on November 28, 2010* -
## Physics

. (a) Calculate the angular momentum of an ice skater spinning at 6.00 rev/s given his moment of inertia is 0.400 kg ⋅ m2. (b) He reduces his rate of spin (his angular velocity) by extending his arms and increasing his moment of inertia. Find the value

*asked on July 14, 2013* -
## Science

What is a factor that limits a technological design? A. a prototype B.a trade-off C.a constraint D.a patent

*asked on September 14, 2017* -
## Algebra 2 Sine Graphing

A sine function has the following key features: Period=4pi Amplitude: 2 Midline y=3 Y intercept; (0,3) The function is a reflection of its parent function over the x axis.

*asked on January 23, 2018* -
## physics

The potential energy of a pair of hydrogen atoms separated by a large distance x is given by U(x)=-C(subscript)6/x^6, where C_6 is a positive constant. What is the force that one atom exerts on the other? Is this force attractive or repulse? I've taken the

*asked on November 11, 2015* -
## science

Which of the following can be used to explain why fossils of the same kinds of organisms can be found in different regions of the world? biogeography adaptation continental drift dispersal I think it is dispersal..but not sure..thank you for your help.

*asked on October 19, 2016* -
## spanish 3

escribe la forma del verbo indicado en el tiempo indicado. yo / tener / future

*asked on May 25, 2017* -
## math

vlad purchased some furniture for his apartment. The total cost was $2942.37. He paid $850 down and financed the rest for 18 months. At the end of the finance period. Vlad owed 2147.48. What annual interest rate compounded monthly eas he being charged?

*asked on June 10, 2013* -
## Physics

A straightforward method of finding the density of an object is to measure its mass and then measure its volume by submerging it in a graduated cylinder. What is the density of a 240-g rock that displaces 89.0 cm3 of water? (Note that the accuracy and

*asked on July 14, 2013* -
## Physics

The person in the drawing is standing on crutches. Assume that the force exerted on each crutch by the ground is directed along the crutch, as the force vectors in the drawing indicate. If the coefficient of static friction between a crutch and the ground

*asked on September 26, 2012* -
## Physics

What is the final velocity of a hoop that rolls without slipping down a 5.00-m-high hill, starting from rest?

*asked on July 14, 2013* -
## physics

20 kg , 30 cm diameter disk is spinning at 300 rpm. How much friction force must be applied to rim to bring the disk to a halt in 3.0s?

*asked on December 15, 2010* -
## physics

Suppose a diving board with no one on it bounces up and down in a simple harmonic motion with a frequency of 3.00 Hz. The board has an effective mass of 10.0 kg. What is the frequency of the simple harmonic motion of a 62.0 kg diver on the board?

*asked on July 28, 2013* -
## Math

Let (7,-3) be a point on the terminal side of theta. Find the exact values of sin of theta, csc of theta and cot of theta?

*asked on November 29, 2016* -
## Science

How are earth and Venus similar? How is Venus different from Earth? Provide two similarities and two differences.

*asked on March 16, 2017* -
## Physics

A golf ball rolls off a horizontal cliff with an initial speed of 12.2 m/s. The ball falls a vertical distance of 17.3 m into a lake below. (a) How much time does the ball spend in the air? (b) What is the speed v of the ball just before it strikes the

*asked on June 18, 2013* -
## Chemistry

1. State specifically how you would make a conclusive test for an iron (III) salt. 2. Which test for iron (II) ions is conclusive. 3. Suppose you have a solution containing both an iron (II) salt and an iron (III) salt. How would you proceed to identify

*asked on November 28, 2010* -
## physics

A 1300-kg car rolling on a horizontal surface has speed v = 65 km/h when it strikes a horizontal coiled spring and is brought to rest in a distance of 2.3 m. What is the spring stiffness constant of the spring?

*asked on March 3, 2010* -
## M ath

Sally has a sum of $26000 that she invests at 9% compounded monthly. What equal monthly payments can she receive over a period of a) 9 years? b) 7 years?

*asked on April 3, 2015* -
## algebra

28 decreased by 6 times a number is the same as the number

*asked on February 18, 2012* -
## Physics

A 35-g block of ice at -14°C is dropped into a calorimeter (of negligible heat capacity) containing 400 g of water at 0°C. When the system reaches equilibrium, how much ice is left in the calorimeter? The specific heat of ice is 2090 J(kg K) and the

*asked on December 5, 2015* -
## physics

In the high jump, Fran's kinetic energy is transformed into gravitational potential energy without the aid of a pole. With what minimum speed must Fran leave the ground in order to lift her center of mass 1.95 m and cross the bar with a speed of 0.70 m/s?

*asked on March 3, 2010* -
## physics

19 cars in a circle at a boom box competition produce a 130 dB sound level at the center of the circle. What is the average sound level(dB) produced there by each, assuming interference effects can be neglected? Please someone help me to solve this

*asked on August 2, 2013* -
## physics

Suppose that 1100 j of work is done by the force 30 n in moving the suitcase a distance of 50 m. At what angle is the force oriented with respect to the ground?

*asked on October 8, 2014* -
## Calculus

Your Porsche's gas mileage (in miles per gallon) is given as a function M(x) of speed x in miles per hour. It is found that M'(x) = 3,600x−2 − 1/ (3,600x−1 + x)2. Estimate M'(10), M'(60), and M'(90). (Round your answers to seven decimal places.)

*asked on September 17, 2013* -
## Social studies

13. Why was Berlin airlift necessary when the Soviet Union isolated West Berlin A. East Berlin had no resources to help West Berlin B. The three nations that controlled West Berlin were not allies C. West Berlin had no access to a river D. West Berlin was

*asked on March 26, 2018* -
## math

The Smiths want to buy a 9 ft. by 12 ft. carpet and center it in a 15 ft. by 20 ft. room. Can a 3 1/2 foot by 12 foot couch be placed against one of the long walls of the room without touching the carpet?

*asked on April 4, 2014* -
## Math

The original price for a pair of sneakers was $70. John bought them on sale for 25% off. The sales tax was 6%. How much did John pay for the sneakers, including sales tax? A $16.80 B $18.55 C $52.50 D $55.65

*asked on May 22, 2017* -
## Math

1. Graph the points A ( -5,0) B ( -4, 3) and C ( 0, -4) A B C D 2. Identify the quadrant in which (3, -6) lies A II B IV C I D III 3. Determine which ordered pair is a solution of y = 2x - 3 A ( -2, 7) B ( 0, 3) C ( -4, -11 D ( 5, -7 5. Graph the linear

*asked on March 23, 2017* -
## math

The number of Roberto's baseball cards is 3/4 the number of David's cards. If Roberto gives 1/2 of his cards to David, what will be the ratio of Roberto's cards to David's cards?

*asked on January 28, 2013* -
## physics

When a pendulum with a period of 2.00000 s is moved to a new location from one where the acceleration of gravity was 9.80 m/s2, its new period becomes 1.99711 s. By how much does the acceleration of gravity differ at its new location? (m/s2)

*asked on July 28, 2013* -
## language arts

Could you check my answer please..thank you Which of the following sentences contains a linking verb? A. Yesterday, Sarah experienced rock climbing for the first time.xxx B. Sarah seemed nervous at first. C. She climbed very well for a beginner. D. I think

*asked on December 10, 2016* -
## science

as 390 g of hot milk cools in a mug, it transfers 30,000 J of heat to the environment. What is the temperature change of milk? The specific heat of milk is 3.9 J/g degree C.

*asked on October 28, 2011* -
## IPC

A hailstone traveling with a velocity of 43 meters/second comes to a virtual stop 0.28 seconds after hitting water. What is the magnitude of its acceleration in the water? a. 12 meters/second2 b. 1.5 × 102 meters/second2 c. 78.6 meters/second2 d. 6.5 ×

*asked on February 6, 2015* -
## math

You require space to service 65 vehicles at any one time. Will a facility measuring 145 ft. by 130 ft. be adequate if each vehicle requires 300 sq.ft.?

*asked on April 15, 2014* -
## Chemistry

If 2.50 g of CuSO4 are dissolved in 9.4 102 mL of 0.34 M NH3, what are the concentrations of Cu(NH3)42+, NH3 and Cu2+ at equilibrium? i tried doing Cu2+ first and i did Kf=5e13= salt/cu2+ nh3+^4 and i did molesCuSO4/.94 L = .01666 M salt so then i did

*asked on March 6, 2009* -
## chemistry

What is the molarity of the following solutions? A. 0.96 g MgCl2 in 500 mL solution B. 9.33 g Na2S in 450 mL solution C. 2.48 g CaF2 in 375 mL solution

*asked on April 7, 2016* -
## math

If Sue worked 6 3/4 hours on Monday, 4 hours on Tuesday, 7 3/4 hours on Wednesday, 8 hours on Thursday, and 5 1/2 hours on Friday, calculate her weekly wage at $7.20 per hour.

*asked on April 8, 2014* -
## 6 grade math

how do you find the height of an area of 245 square inches and a base of 14 inches.

*asked on March 19, 2012* -
## AP Physics

A merry-go-round rotates at the rate of.2rev/s with an 80kg man standing at a point 2m from the axis ofrotation. (A)What is the new angular speed when the man walksto a point 1m from the center? Assume that the merry-go-round is a solid 25kg cylinder of

*asked on March 4, 2010* -
## geography

what is the value of igneous rocks to humankind?

*asked on April 21, 2014* -
## math

An alloy of copper is 10% copper and weighs 25 pounds. A second alloy is 18% copper. How much (to the nearest tenth lb.) of the second alloy must be added to the first alloy to get a 13% mixture.

*asked on April 6, 2014* -
## math

If the angle of declination is known, a surveyor would use_______ to find the length x. The cosine of a 50° angle is_______ this represents the value created when length x is divided by 90 feet. If the angle of declination changed to 60°, the cosine

*asked on April 5, 2014* -
## geometry

Is it possible for two points on the surface of a prism to be neither collinear nor coplanar?

*asked on August 14, 2012* -
## Physics

A 3.00-liter aluminum cylinder at 5.00°C is filled to the brim with gasoline at the same temperature. If the aluminum and gasoline are warmed to 52.0°C, how much gasoline spills out? [Hint: Be sure to account for the expansion of the container. Also,

*asked on June 15, 2011* -
## math calculus

The concentration C (in milligrams per milliliter) of a drug in a patient's bloodstream t hours after injection into muscle tissue is modeled by C = 3t/26 + t^3 Use differentials to approximate the change in the concentration when t changes from t = 1 to t

*asked on May 4, 2013* -
## physics

A spring has a length of 0.190 m when a 0.300 kg mass hangs from it, and a length of 0.750 m when a 2.80 kg mass hangs from it. (a) What is the force constant of the spring? (b) What is the unloaded length(m) of the spring?

*asked on July 28, 2013* -
## Thermo engineering

The driveshaft of a building’s air-handling fan is turned at 300 RPM by a belt running on a 0.3-m-diameter pulley. The net force applied by the belt on the pulley is 2000 N. determine the torque applied by the belt on the pulley, in N.m, and the power

*asked on May 10, 2011* -
## physics

An aluminum can is filled to the brim with a liquid. The can and the liquid are heated so their temperatures change by the same amount. The can’s initial volume at 8 °C is 4.8 × 10-4 m3. The coefficient of volume expansion for aluminum is 69 × 10-6

*asked on July 25, 2013* -
## Physics

a 55 kg skateboarder starts out with a speed of 1.8 m/s. he does +80 J of work on himself by pushing with his feet against the ground. in addition, the friction does -265 J of work on him. in both cases, the forces doing the work are nonconservative. the

*asked on December 4, 2010* -
## Calculus

The base of a solid is the circle x^2 + y^2 = 9. Cross sections of the solid perpendicular to the x-axis are squares. What is the volume, in cubic units, of the solid? A. 18 B. 36 C. 72 D. 144 Please help. Thank you in advance.

*asked on June 25, 2019* -
## physics

Two point charges totaling 9.00 µC exert a repulsive force of 0.300 N on one another when separated by 0.596 m. (A) What is the charge on each? (B) What is the charge on each if the force is attractive? smallest charg

*asked on February 28, 2013* -
## Physics

Suppose a straight 1.25 mm diameter copper wire could just "float" horizontally in air because of the force of the Earth's magnetic field B, which is horizontal, perpendicular to the wire, and of magnitude 5.00 multiplied by 10-5 T. What current would the

*asked on February 10, 2011* -
## Information Systems

Problem #2 from page 173 Given the following business scenario, create a Crow’s Foot ERD using a specialization hierarchy if appropriate. Tiny Hospital keeps information on patients and hospital rooms. The system assigns each patient a patient ID number.

*asked on February 25, 2013* -
## Problem solving (point of intersection)

Alpine Valley charges $10/hr for lessons and $40 for the lift ticket and snowboard rental. Chicopee Hills charges $20/hr which includes lessons, lift ticket and rentals. Which resort would you choose? Equation A: y=. X+ Equation B: y=. X+ Decide on a

*asked on July 13, 2015* -
## Art

what idea did the halos on the heads of Pichore's main subjects emphasize A) plentiful wisdom •• B) Exceptional power C) Divine connection D) extraordinary creativity Correct me

*asked on February 19, 2016* -
## math

The garage you work for as an auto mechanic measures 230 ft. by 150 ft and handles 69 cars. Using the existing garage as a model, how much space would you plan to have in your garage?

*asked on April 19, 2014* -
## Physics

A particle's initial velocity, given as components, is vx = 2.0 m/s and vy = 3.0 m/s. (a) Calculate its velocity 1.5 s later if it experiences an acceleration, given as components, of ax = -1.0 m/s2 and ay = -2.0 m/s2. (b) Calculate the particle's

*asked on June 26, 2019* -
## physics

(a) Two point charges totaling 8.50 µC exert a repulsive force of 0.100 N on one another when separated by 0.839 m. What is the charge on each? smallest charge (µC) largest charge (µC) (b) What is the charge on each if the force is attractive? smallest

*asked on August 26, 2013* -
## physics

A physicist at a fireworks display times the lag between seeing an explosion and hearing its sound, and finds it to be 0.800 s. (a) How far away(m) is the explosion if air temperature is 22.0°C, neglecting the time taken for light to reach the physicist?

*asked on July 31, 2013* -
## Chemistry

Are my answers correct? Identify each energy exchange as primarily heat or work and determine weather the sign of ?E is positive or negative for the system. A. A rolling billiard ball collides with another billiard ball. The first ball (system) stops

*asked on April 9, 2014* -
## Physics

A particle accelerates from rest at 2.0 m/s2 for 2.0 s, then at 1.0 m/s2 for 3.0 s, then at constant velocity for 4.0 s. Sketch a graph of velocity versus time and determine (a) the average acceleration during the entire motion, and (b) the displacement.

*asked on June 26, 2019* -
## physics

A physicist at a fireworks display times the lag between seeing an explosion and hearing its sound, and finds it to be 0.800 s. (a) How far (m)away is the explosion if air temperature is 22.0°C, neglecting the time taken for light to reach the physicist?

*asked on July 31, 2013* -
## Physics

A 0.02 kg-lead bullet traveling 200 m/s strikes an armor plate and comes to a stop. If all of it's energy is converted to heat that it absorbs, what is the temperature change?

*asked on June 25, 2011* -
## physics

A 0.662-kg basketball is dropped out of a window that is 6.32 m above the ground. The ball is caught by a person whose hands are 1.82 m above the ground. (a) How much work is done on the ball by its weight? What is the gravitational potential energy of the

*asked on July 8, 2013* -
## Geometry

A 20 meter long cable is used to support a telephone pole, holding it perpendicular to the ground. If the cable forms a 60 degree angle with the ground, how high up the pole should the cable be attached?

*asked on December 12, 2016* -
## English

Which of the following would most likely be an entry in a sentence outline? A. Education tool B. Education can change a person's life C. Education as a pathway D. Education beyond high school versus education beyond college My answer was D I got it wrong

*asked on March 23, 2015* -
## Chemistry

Air bags are activated when a severe impact causes a steel ball to compress a spring and electrically ignite a detonator cap. This causes sodium azide (NaN3) to decompose explosively according to the following reaction. 2 NaN3(s) 2 Na(s) + 3 N2(g) What

*asked on November 6, 2010* -
## Calculus

1. The function is continuous on the interval [10, 20] with some of its values given in the table above. Estimate the average value of the function with a Left Hand Sum Approximation, using the intervals between those given points. x 10 12 15 19 20 f(x)

*asked on July 30, 2019* -
## Calculus

For Questions 1–3, use the differential equation given by dx equals xy/3, y > 0. Complete the table of values x −1 −1 −1 0 0 0 1 1 1 y 1 2 3 1 2 3 1 2 3 dy/dx ? ? ? ? ? ? ? ? ? Find the particular solution y = f(x) to the given differential

*asked on July 30, 2019* -
## Calculus

Use geometry to evaluate the integral from 0 to 6 of the function f of x, dx for the system of equations: f(x)= 3 for x LESS than or EQUAL to 3 and equals 6-x for x > 3. A. 27 B.13.5 C.12 D.10.5 I could really use some help. Thank you!

*asked on June 12, 2019* -
## math

Note: Enter your answer and show all the steps that you use to solve this problem in the space provided. A cylinder has diameter 34 m and height 27 m. A label at bottom states drawing not to scale. Find the volume of the cylinder. Use 3.14 for π PLEASE

*asked on April 4, 2019* -
## Physics

A ball is fired from a height of 1.4 m above ground, at a speed of 3.6 m/s, and at an angle of 25° above horizontal. (a) What is the peak height of the ball above ground? (b) Where does the ball land? Ignore Earth's atmosphere, curvature, and rotation.

*asked on June 25, 2019* -
## physics

If 2.00 multiplied by 1020 electrons move through a pocket calculator during a full day's operation, how many coulombs of charge moved through it?

*asked on August 21, 2013* -
## Calculus

Let F of x equals the integral from 1 to 3 times x of the natural logarithm of t squared. Use your calculator to find F″(1). A. 12 B. 6 C. 4 D. 1/9 Find the range of the function f of x equals the integral from 0 to x of the square root of the quantity

*asked on July 30, 2019* -
## Chemistry

A Sample of M2O3 weighing 11.205g is converted to 15.380g of MCL3, where M is the unknown metal, then what is the identity of M?

*asked on February 5, 2016* -
## physics

An 8 hour exposure to a sound level of 95.0 dB may cause hearing damage. What energy in joules falls on a 0.850 cm diameter eardrum so exposed?

*asked on July 31, 2013* -
## physics

An 8 hour exposure to a sound level of 95.0 dB may cause hearing damage. What energy in joules falls on a 0.850 cm diameter eardrum so exposed? I try to use k = IAT = (1*10^-3)(0.0085^2)(8*3600)=0.00208 but answer is not correct.

*asked on August 2, 2013* -
## Physics

A particle starts from rest and travels in a circular path of diameter 10.0 m. If the tangential component of its acceleration is 2.5 m/s2, determine (a) the speed at the instant it has traveled one third of a lap around the circle, and (b) the magnitude

*asked on June 26, 2019* -
## physics

Two point charges exert a 2.50 N force on each other. What will the force become if the distance between them is increased by a factor of 5?

*asked on August 24, 2013* -
## physics

A physicist at a fireworks display times the lag between seeing an explosion and hearing its sound, and finds it to be 0.800 s. (a) How far (m)away is the explosion if air temperature is 22.0°C, neglecting the time taken for light to reach the physicist?

*asked on August 1, 2013* -
## Economics

A perfectly competitive painted necktie industry has a large number of potential entrants. Each firm has an identical cost structure such that long-run average cost is minimized at an output of 20 units . The minimum average cost is $10 per unit. Total

*asked on November 5, 2017* -
## physics

(a) A solar collector is 12.0% efficient in gathering solar energy and converting it to heat. If the average intensity of sunlight on one day is 700 W/m2, what area(m^2) should your collector have to gather energy at the rate of 150 W? (b) What is the

*asked on July 30, 2013* -
## Calculus

I also have these other four question I need help on please!! 1. The graph of y = f ′(x), the derivative of f(x), is shown below. Given f(4) = 6, evaluate f(0). A. -2 B. 2 C. 4

*asked on July 29, 2019* -
## Physics

Imagine a boat that travels at 3.0 m/s in still water. (a) In which direction should the boat point its bow to travel directly across a 0.50-km wide river when the river flows at 1.5 m/s? (b) What is the time interval for the trip, expressed in minutes?

*asked on June 25, 2019* -
## Calculus

Which of the following integrals correctly computes the volume formed when the region bounded by the curves x^2 + y^2 = 25, x = 4 and y = 0 is rotated around the y-axis? A. pi ∫ upper bound of 3 and lower bound of 0 ( sqrt(25 - y^2) -4)^2 dy B. pi ∫

*asked on June 24, 2019* -
## Calculus

1. The graph of f ′′(x) is continuous and decreasing with an x-intercept at x = –3. Which of the following statements must be true? A. The graph of f is always concave down. B. The graph of f has an inflection point at x = –3. C. The graph of f has

*asked on July 31, 2019* -
## Physics

A 4.00-kg block rests on a 30.0° incline. If the coefficient of static friction between the block and the incline is 0.700, what magnitude horizontal force F must act on the block to start it moving up the incline, given g= 9.80m/s^2?

*asked on May 4, 2016* -
## physics

Calculate the net work output of a heat engine following path ABCDA in Figure 14.30, where horizontal axis is V and each unit is 0.5*10^-3 m^3, V1 = 1.0*10^-3 m^3 and V2 = 4.0*10^-3 m^3. The vertical axis is P(N/m^2); A is (1.0*10^-3,2.6*10^6), B is

*asked on July 25, 2013*