# Elisa

Popular questions and responses by Elisa
1. ## physics

A jet airliner moving initially at 300 mi/h due east enters a region where the wind is blowing at 100 mi/h in a direction 26.0° north of east. What is the new velocity of the aircraft relative to the ground? in m/h at degrees North of east.

2. ## Physics

One of the fastest recorded pitches in major-league baseball, thrown by Billy Wagner in 2003, was clocked at 101.0 mi/h . If a pitch were thrown horizontally with this velocity, how far would the ball fall vertically by the time it reached home plate, 60.5

3. ## Physics

Two blocks are fastened to the ceiling of an elevator as in Figure P4.19. The elevator accelerates upward at 2.00 m/s2. The blocks both have a mass of 14.0 kg. Find the tension in each rope. top rope: bottom rope:

4. ## physics

A 705 N man stands in the middle of a frozen pond of radius 4.0 m. He is unable to get to the other side because of a lack of friction between his shoes and the ice. To overcome this difficulty, he throws his 1.2 kg physics textbook horizontally toward the

5. ## Math

The ratio of golf balls to tennis balls in the coach's bag is 20 to 5. If there are 100 golf balls in the bag, how many tennis balls are in the bag?

6. ## physics

An object with mass m1 = 5.00 kg, rests on a frictionless horizontal table and is connected to a cable that passes over a pulley and is then fastened to a hanging object with mass m2 = 9.0 kg, as shown in Figure P4.30. Find the acceleration of each object

7. ## physics

In a popular amusement park ride, a rotating cylinder of radius 4.00 m is set in rotation at an angular speed of 5.00 rad/s. The floor then drops away, leaving the riders suspended against the wall in a vertical position. What minimum coefficient of

8. ## Math

Brent counted 10 red cards, 10 black cards, and 20 blue cards in a deck of cards. What is the ratio of red cards to the other cards?

9. ## physics

An airplane flies 200 km due west from city A to city B and then 280 km in the direction of 30.5° north of west from city B to city C. (a) In straight-line distance, how far is city C from city A? (b) Relative to city A, in what direction is city C? The

10. ## MATH HW HELP!!

stuart daniels estimates that he will need 25,000 to set up a small business in 7 years. how much must Stuart invest now at 12%interest compounded quarterly to achieve his goal?

11. ## Chemistry

Is this reaction exothermic or endothermic? Fe(NO3)3+ NaSCN

12. ## algebra

A 125-ft diagonal brace on a bridge connects a support of the center of the bridge to a side support on the bridge. The horizontal distance that it spans is 25 ft longer than the height that it reaches on the side of the bridge. Find the horizontal and

13. ## algebra

Factor the expression 16x^2-72xy+81y^2 into a product of binomials.

14. ## Intermediate Algebra

Factor completely. If a polynomial is prime, state this 9 + 8t^2 - 18t

15. ## Intermiediate Algebra

Factor completely. Remember to look first for a common factor. If a polynomial is prime, state this -4t^2 + 64

16. ## Calculus

Suppose that the number of bacteria in a culture at time t is given by N = 4950 ( 28 + t*e ^(-t/24)) Find the LARGEST and SMALLEST number of bacteria in the culture during the time interval 0 ≤ t ≤ 140

17. ## Calculus

Suppose that the number of bacteria in a culture at time t is given by N = 4950 ( 28 + t*e ^(-t/24)) Find the LARGEST and SMALLEST number of bacteria in the culture during the time interval 0 ≤ t ≤ 140 .

18. ## physics

A bat flying at 6.00 m/s emits a chirp at 40.0 kHz. If this sound pulse is reflected by an insect moving away from the bat at 2.00 m/s, what is the frequency of the echo received by the bat? Assume the air temperature is 25.0 ˚C. Would I need two

19. ## Physics

There is a parabolic position vs time graph. Which of these is true: The object moves 1. in a parabolic trajectory. 2. along a straight line. 3. along an arc of a circle wouldn't 1 and 3 produce the same/similar position graph?

20. ## physics

A quarterback throws a football toward a receiver with an initial speed of 21 m/s at an angle of 30° above the horizontal. At that instant, the receiver is 12 m from the quarterback. In what direction and with what constant speed should the receiver run

21. ## physics

A car is parked on a cliff overlooking the ocean on an incline that makes an angle of 20.0° below the horizontal. The negligent driver leaves the car in neutral, and the emergency brakes are defective. The car rolls from rest down the incline with a

22. ## Physics

A quarterback throws a football toward a receiver with an initial speed of 21 m/s at an angle of 30° above the horizontal. At that instant, the receiver is 12 m from the quarterback. In what direction and with what constant speed should the receiver run

23. ## Physics

A boat moves through the water of a river at 5 m/s relative to the water, regardless of the boat's direction. If the water in the river is flowing at 1.3 m/s, how long does it take the boat to make a round trip consisting of a 215 m displacement downstream

24. ## Physics

A boat moves through the water of a river at 5 m/s relative to the water, regardless of the boat's direction. If the water in the river is flowing at 1.3 m/s, how long does it take the boat to make a round trip consisting of a 215 m displacement downstream

25. ## physics

1. A centrifuge in a medical laboratory rotates at an angular speed of 3650 rev/min. When switched off, it rotates through 50.0 revolutions before coming to rest. Find the constant angular acceleration of the centrifuge. 2. A ball of mass 0.120 kg is

26. ## physics

Calculate the magnitude of the linear momentum for the following cases. (a) a proton with mass 1.67 10-27 kg, moving with a speed of 4.00 106 m/s (b) a 16.5 g bullet moving with a speed of 270 m/s (c) a 70.5 kg sprinter running with a speed of 12.5 m/s (d)

27. ## physics

A 45.0 kg girl is standing on a 163 kg plank. The plank, originally at rest, is free to slide on a frozen lake, which is a flat, frictionless surface. The girl begins to walk along the plank at a constant velocity of 1.45 m/s relative to the plank. (a)

28. ## physics

1. It has been suggested that rotating cylinders about 11 mi long and 5.2 mi in diameter be placed in space and used as colonies. What angular speed must such a cylinder have so that the centripetal acceleration at its surface equals the free-fall

29. ## physics

calculate your average walking speed when you step 1.0 m in 0.5 s

30. ## math

Twenty-five is equal to one more than eight times a number. What is the number?

31. ## Math

Nelly spends 25% of her free time surfing the Internet. If she spends approximately 1 hour per day surfing the Internet, how many hours of free time does she have each day?

32. ## Physics

How does an electric motor work, linking to the theory of electromagnetism? I have already identified a few laws: -Ohms -Faraday's

34. ## Education

Personal Reflection: what attitudes, skills, and values, do you do as an individual, need to develop in order to implement a multicultural/anti-bias curriculum? I have to write a paper on that question and I don't understand what this mean? Can anyone

35. ## math

28E − 7 = 0 would I add 7 to the 0 then divide 28 by 7 but the answer don't check out

36. ## math

Simplify the expression. (x − 3)(2x − 4) − (x + 2)(x − 6)=

37. ## math

please simplify the expreesion: (2x − 1)(x^2 + 3x − 3)=

38. ## math

Simplify the expression. 5(x − 1) − 3(x^2 + 4x + 5)- 8(x+7)=

40. ## math

can you help me factor this one? x^2 + x - 20=?

41. ## math

please factor this: x^2 + 9x +18=?

44. ## Algebra

A dress normally selling for \$60 was on sale for \$48. What was the percent discount?

45. ## Algebra

A box contains 4 quaters, 3 dimes, and 2 nickels. you draw out two coins and keep them both. What is the probability that both are quaters?

46. ## algebra

At 3:00 pm the temperature was 2* below zero. It then fell 4* in the next 2 hours. what was the temperature at 5:00pm?

47. ## Chemistry

Acid spills are often neutralized with sodium carbonate. For example Na2CO3 (s) + H2SO4 (aq)  Na2SO4 (aq) + CO2 (g) + H2O (l) An instructor dropped a 2.50 L bottle of 18.0 M H2SO4 on a cement floor. How much sodium carbonate would be required to

48. ## american history

I must provide a historical overview of the evolution of U.S. cities from colonial times to the present. could you please provide me with a starting point and some web resources. thanks.

49. ## physics

A ball thrown straight upward returns to its original level in 2.50s. A second ball is thrown at an angle of 36.degrees above the horizontal. What is the initial speed of the second ball if it also returns to its original level in 2.50

50. ## Algebra

Megan factored the expression 72x^2-43x+6 as (9x-3)(8x-2). But when Jacob applied the FOIL principle and multiplied out (9x-3)(8x-2), he got72x^2-42x+6; thus, Megan’s solution does not appear to check. Why is that? Please help Megan to understand this

51. ## algebra

The length of a rectangle is 2 meters more than its width. If the area is 63 square meters, what are the length and width?

52. ## algebra

Use the “difference of squares” rule to factor the following expression: 100a^6-64b^8

53. ## algebra

Megan factored the expression 72x^2-43x+6 as (9x-3)(8x-2). But when Jacob applied the FOIL principle and multiplied out (9x-3)(8x-2), he got72x^2-42x+6; thus, Megan’s solution does not appear to check. Why is that? Please help Megan to understand this

54. ## algebra

Factor out the greatest common factor from the expression 9a2b3 – 12a2b4 – 24a3b

55. ## algebra

Factor out the greatest common factor from the expression 36x^3-30x^2

56. ## algebra

Factor the following expression completely: 45x^3y – 80xy

15t^2+7t=2

Abby rows 10 km upstream and 10 km back in a total time of 3 hr. The speed of the river is 5km/h. Find Abby’s speed in still water.

59. ## Intermedia Algebra

Solve by factoring: 2a^2 − 3a = −5

60. ## Intermidiate Algebra

Andrew factored the expression -12x^3-28x^2-3x as -4x (3x^2-7x+9). But when Melissa applied the distributive law and multiplied out -4x (3x^2-7x+9), she got -12x^3+28x^2-36x; thus, Andrew’s solution does not appear to check. Why is that? Please help

61. ## Intermidiate Algebra

The area of a rectangular athletic field is represented by the expression 25y^2-4z^2 square meters. Write an algebraic expression to represent one possible set of dimensions (in the sense “length times width”) of the athletic field. Include correct

62. ## intermidiate Algebra

The area of a rectangular athletic field is represented by the expression 16y^7+32y^5+80y^3 square meters. Write an algebraic expression to represent one possible set of dimensions (in the sense “length times width”) of the athletic field. Include

63. ## Intermediate Algebra

Factor by grouping, if possible, and check 5x3 + 4x2 − 10x – 8

64. ## chemistry

what volume of oxygen gas is needed to completely combst 0.202L of butane (c4h10)gas?

65. ## Math

A particle is moving so that its velocity, v(t) = t-64/t^2 for 2≤t≤6. find the total distance traveled by the particle.

66. ## math

A particle moves along the s-axis. Use the given information to find the position of the particle. v(t)=8t3 ; s(0) = 5.

A particle moves along the s-axis. Use the given information to find the position of the particle. v(t) = 8t3; s(0) = 5.

68. ## Calculus

Suppose that the number of bacteria in a culture at time t is given by N = 4950 ( 28 + t*e ^(-t/24)) Find the LARGEST and SMALLEST number of bacteria in the culture during the time interval 0 ≤ t ≤ 140

A particle is moving so that its velocity, v(t) = t-64/t^2 for 2≤t≤6. find the total distance traveled by the particle.

70. ## Pre Algebra

The first side of a triangle is 8 meters longer than twice the second side. The third side is 3 times the second side. The perimeter is 128 meters. Find the lengths of the three sides.

71. ## Language

Instead, he enjoyed looking for hours and hours... In this phrase is the word looking a noun, adjective,verb, or an adverb?

72. ## Algebra 1

Write the equation in standard form for the line that passes through (6, -1) and (10,-*) So far I have -8-1 is -9 and 10-6 is 4, is the -9 correct? Then y plus 10 equals 9/4(x - 8) Then multiply by 2 so 2y plus 20 equals 18/4x - 146/4 Is this correct so

73. ## Algebra 1

Graph y-7 equals 9(x plus 6) So 9x plus 54 54 plus 7 is 61 So y equals 9x plus 61. is it correct?

74. ## Algebra 1

Write an equation in standard form for the line through (9, -2) and (13, -8) Do I solve this by doing y2-y1/x2-x1. That would give me the slope and then plug in the 13 for the x and -8 for the y?

75. ## Algebra 1

Could you please show me how to do this. Write an equation of the vertical and horizontal lines that pass through the given point (6,-6) y equals? x equals ?

76. ## algebra

Graphthe equation y plus 6 equals 1/8(x-2 1/8x - 2/8 add 2/8 to 6, so 61 times 8/8 makes it 48/8 plus 2/8 is 50/8 mx plus c would be 1/8 plus 50/8. Is this correct so afr? If so how do I graph 50/8? Do I just put at 50 on the y axis and do 1/8 rise over

77. ## algebra 1

Write an equation in point slope for for the line thatpasses through (4,5) and has a slope of 6 I got -19. Is this correct?

78. ## fraction help algebra

Write the equation passing through the points (-9, 6 ) and (1, -5). The worksheet has multiple choice, so I know y intercept is either 39/10 or -39/10. I have -11/10x plus b then -11 (1) is -11 10(1) is 10 Then -5 plus 11/10 I change -5 to -15/10 but I'm

79. ## algebra again

Write an equation that passes through the points (4, 3) and (2, -2) I have -2 -3 is -5 and 2-4 is -2 so y equals -5/2x plus b. I put in 2,-2 into the equation to get the y intercept, so 2 equals -5/2 times 2 plus b -5/2(2) is -10/-4 reduce to -5/-2 Now add

80. ## algebra 1

Write the equation for the line that passes through the point (6,7) and has a slope of 1/2. Give as a simplified fraction. Again, I have y equals 1/2x but not sure for the rest.

81. ## algebra

Write an equation of a line that passes through the points (-6,7) and has a slope of -4 How do I do this? it would be y equals -4x but not sure how to do the rest.

82. ## Algebra

How come (2xy^2)^3 is equal to 8x^3 y-6? I thought that six exponent should be a five since you add them together. So 2 and 3 should be five. But why is this?

83. ## math

Hi! I have a question Heres the problem: 3-2[6-(4y-1)] I got -8y-11 but it wasn't right and I don't know what i did wrong help please!

84. ## math

in a school of 100 students, 59 are taking math, 51 are in english, 35 are in history, 24 are in both math and english, 19 are in both english and history, 13 in both math and history, and 11 in all three courses. how many students are taking: a) none of

85. ## physics

A stone is thrown downward into a well with an initial speed of 5.00 m/s. The sound of splash is heard 1.50 s later. Find the depth of the well if the air temperature is 15.0 ˚C?

86. ## physics

A uniform string fixed at one end passes over a pulley and then is attached to a hanging object. The string is horizontal between the fixed end and the pulley. When you let the hanging object oscillate in the vertical plane, the fundamental frequency of

87. ## physics

A simple pendulum with a length of 1.50 m is suspended from the ceiling of a train. What is the period of simple harmonic motion for the pendulum if the train is moving up an incline of 15.0˚ with an acceleration of 3.00 m/s²? Don't know how to do,

88. ## physics

A bat flying at 5.0 m/s emits a chirp at 35 kHz. If this sound pulse is reflected by a wall, what is the frequency of the echo received by the bat? I keep getting the wrong answer, don't understand.

89. ## Physics

A simple pendulum is 9.00 m long. (a) What is the period of simple harmonic motion for this pendulum if it is hanging in an elevator accelerating upward at 2.00 m/s2? I keep getting 6.7, but it's wrong

90. ## Physics

Please help. I got 338.82 for the velocity and wanted to get the distance, but I can't seem to do it because I don't have the wavelength. Please help! A stone is dropped from rest into a well. The sound of the splash is heard exactly 2.20 s later. Find the

91. ## physics: drwls

drwls for the question below, the answer seems to be wrong: The four tires of an automobile are inflated to a gauge pressure of 1.8 multiplied by 105 Pa. Each tire has an area of 0.025 m2 in contact with the ground. Determine the weight of the automobile.

92. ## Physics

Can't get correct answer An object weighing 340 N in air is immersed in water after being tied to a string connected to a balance. The scale now reads 260 N. Immersed in oil, the object weighs 290 N. (a) Find the density of the object. kg/m3 (b) Find the

93. ## physics

Determine the elongation of the rod in if it is under a tension of 5.7E10^3 N. The rod is made of aluminum and copper. From the aluminum to the copper section it measures 1.3m and from the copper section to the end it measures 2.6m with a radius of 0.2cm.

94. ## physics

Determine the elongation of the rod in if it is under a tension of 5.7E10^3 N. The rod is made of aluminum and copper. From the aluminum to the copper section it measures 1.3m and from the copper section to the end it measures 2.6m with a radius of 0.2cm.

95. ## Physics

The four tires of an automobile are inflated to a gauge pressure of 1.8E10^5 Pa. Each tire has an area of 0.025 m2 in contact with the ground. Determine the weight of the automobile. I was helped with this before, but the answer was wrong. Can someone

96. ## physics

The four tires of an automobile are inflated to a gauge pressure of 1.8 multiplied by 105 Pa. Each tire has an area of 0.025 m2 in contact with the ground. Determine the weight of the automobile. No idea how to start, please help.

97. ## physics

A 175 kg merry-go-round in the shape of a uniform, solid, horizontal disk of radius 1.50 m is set in motion by wrapping a rope about the rim of the disk and pulling on the rope. What constant force would have to be exerted on the rope to bring the

98. ## physics

A bat hits a moving baseball. If the bat delivers a net eastward impulse of 0.7 N-s and the ball starts with an initial horizontal velocity of 3.8 m/s to the west and leaves with a 5.2 m/s velocity to the east, what is the mass of the ball (in grams)?

99. ## physics

The force sensor measures the force on the sensor due to the bumper, but the cart's momentum change arises from the force on the cart due to the bumper. Which of the following facts are needed to assert that the magnitude of these two forces are nearly