# Justin

Most popular questions and responses by Justin
1. ## 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

2. ## Geometry

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

3. ## 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

4. ## 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

5. ## Science

Explain what Maria and craters are and how they formed.

6. ## 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?

7. ## 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

8. ## 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?

9. ## 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.

10. ## 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

11. ## 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.

12. ## 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

13. ## 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

14. ## Science

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

15. ## 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.

16. ## 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

17. ## 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.

18. ## spanish 3

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

19. ## 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?

20. ## 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

21. ## 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

22. ## Physics

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

23. ## 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?

24. ## 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?

25. ## 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?

26. ## Science

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

27. ## 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

28. ## 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

29. ## 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?

30. ## 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?

31. ## algebra

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

32. ## 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

33. ## 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?

34. ## 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

35. ## 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?

36. ## 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.)

37. ## 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

38. ## 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?

39. ## 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

40. ## 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

41. ## 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?

42. ## 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)

43. ## 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

44. ## 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.

45. ## 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 ×

46. ## 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.?

47. ## 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

48. ## 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

49. ## 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.

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

51. ## 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

52. ## geography

what is the value of igneous rocks to humankind?

53. ## 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.

54. ## 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

55. ## geometry

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

56. ## 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,

57. ## 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

58. ## 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?

59. ## 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

60. ## 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

61. ## 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

62. ## 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.

63. ## 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

64. ## 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

65. ## 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.

66. ## 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

67. ## 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

68. ## 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?

69. ## 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

70. ## 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

71. ## 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?

72. ## 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

73. ## 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.

74. ## 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?

75. ## 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?

76. ## 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

77. ## 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?

78. ## 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

79. ## 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

80. ## 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)

81. ## 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

82. ## 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!

83. ## 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

84. ## 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.

85. ## 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?

86. ## 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

87. ## 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?

88. ## 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?

89. ## 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.

90. ## 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

91. ## 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?

92. ## 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?

93. ## 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

94. ## 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

95. ## 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

96. ## 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?

97. ## 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 ∫

98. ## 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