# Rachel

Most popular questions and responses by Rachel
1. ## Physics

The magnitudes of the four displacement vectors shown in the drawing are A = 14.0 m, B = 11.0 m, C = 12.0 m, and D = 25.0 m. Determine the (a) magnitude and (b) direction for the resultant that occurs when these vectors are added together. Specify the

2. ## Chemistry

3NO2(g) + H2O(l) → 2HNO3(aq) + NO(g) standard enthalpy: -133.5 Find the change in internal energy for this reaction. Enter in kJ.

3. ## Geometry

The equation (x + 6)^2 + (y + 4)^2 = 36 models the position and range of the source of a radio signal. Describe the position of the source and the range of the signals.

4. ## Physics

A ball is shot from the ground into the air. At a height of 9.1 m, the velocity is observed to be v = (6.6 + 5.7 ) m/s, with horizontal and upward. (a) To what maximum height does the ball rise? m (b) What total horizontal distance does the ball travel? m

5. ## Chemistry 120

* If 13.3 kilograms of Al2O3(s), 58.4 kilograms of NaOH(l), and 58.4 kilograms of HF(g) react completely, how many kilograms of cryolite will be produced? * Which reactants will be in excess? *What is the total mass of the excess reactants left over after

6. ## phyics

A dart leaves the barrel of a blowgun at a speed v. The length of the blowgun barrel is L. Assume that the acceleration of the dart in the barrel is uniform. Find a time that the dart moves inside the barrel. Express your answer in terms of the variables L

7. ## chemistry

In the reaction 2SO2 (g) + O2 (g) 2SO3 (g), which change would cause the greatest increase in the concentration of SO3?

8. ## calculus

the cross section of a 5-ft long trough is an isosceles trapezoid with a 2 foot lower base, a 3-foot upper base, and an altitude of 2 feet. water is running into the trough at a rate of 1 cubic foot per minute. how fast is the water level rising when the

9. ## AP Calc. AB

1.If an arrow is shot upward on the moon with a velocity of 50 m/s its height (in meters) after t seconds is given by H = 50t - 0.66t2. With what velocity will the arrow hit the moon? a. -49.5 b. -47 c. -50.1 d. -50 e. -51 2.If an arrow is shot upward on

10. ## Gen Chem 1

A tanker truck carrying 2.01×10^3kg of concentrated sulfuric acid solution tips over and spills its load. The sulfuic acid is 95.0% H2SO4 by mass and has a density of 1.84g/L. Sodium Carbonate (Na2CO3)is used to neutralize the the sulfuric acid spill. How

11. ## Chemistry

A base has a Kb of 2.5 x 10–11. Which of the following statements is true? This is a concentrated base. This base ionizes slightly in aqueous solution. This is a strong base. An aqueous solution of this base would be acidic.

12. ## Physics

A child's game consists of a block that attaches to a table with a suction cup, a spring connected to that block, a ball, and a launching ramp. By compressing the spring, the child can launch the ball up the ramp. The spring has a spring constant k, the

13. ## Physics

Julie throws a ball to her friend Sarah. The ball leaves Julie's hand a distance 1.5 meters above the ground with an initial speed of 24 m/s at an angle 32 degrees; with respect to the horizontal. Sarah catches the ball 1.5 meters above the ground. What is

14. ## Pre calc

sin(θ − ϕ); tan(θ) = 5/12 θ in Quadrant III, sin(ϕ) = − sqaure root 10/10 ϕ in Quadrant IV I tried this numerous times can somone please help me

15. ## chemistry

Aqueous silver nitrate reacts with aqeous potassium iodide in a double-replacement reaction to produce a precipitate of silver iodide. If 34.6 ml of 0.563 M silver nitrate are used with 148.4 ml of potassium iodide: a) What molarity of potassium iodide

16. ## Physics

A certain spring stretches 5.8cm when a load of 38N is suspended from it. How much will the spring stretch if 48N is suspended from it (and it doesn't reach its elastic limit)?

17. ## Chem

A sealed container holding 0.0255 L of an ideal gas at 0.989 atm and 71 °C is placed into a refrigerator and cooled to 45 °C with no change in volume. Calculate the final pressure of the gas.

18. ## Physics

Suppose that in the same Atwood setup another string is attached to the bottom of m1 and a constant force f is applied, retarding the upward motion of m1. If m1 = 5.30 kg and m2 = 10.60 kg, what value of f will reduce the acceleration of the system by 50%?

19. ## Chemistry H

"When you pulled the steel wool apart, you found that the mass was unchanged. When you heated the steel wool, you found that the mass changed. Explain."

20. ## chemistry

Determine the theoretical yield of C when each of the following amounts of A and B are allowed to react in the generic reaction: A+2B-->3C 1) 1mol A; 1 mole B 2) 1mole A; 3 mole B 3) 2mole A; 2 mole B 4) 32mole A; 68 mole B

21. ## Chemistry

What is the hybridization of phosphorous in a P4 molecule

22. ## Physical Science

A 0.6-g peanut is burned beneath 50 g of water, which increases in temperature from 22degreesC to 50 degreesc. What is the exact food value of the peanut? (Assuming a 40% efficiency)

23. ## Chemistry

what is the name for the following coordination compounds or ions? 1. [Al(H2O)6] Br3 2. [Cr(NH3)6] Cl3 3. K3[FeF6] 4. [Zn(OH)4]-2

24. ## Physics

A loaded penguin sled weighing 60 N rests on a plane inclined at 20° to the horizontal. Between the sled and the plane the coefficient of static friction is 0.27, and the coefficient of kinetic friction is 0.13. (a) What is the minimum magnitude of the

25. ## chemistry

write a net ionic equation for the following: 1)Iron (III) chloride reacts with Potassium hydroxide to produce Iron (III) oxide, Potassium chloride, and Hydrogen gas. 2)Hydrochloric acid reacts with Potassium carbonate to produce Potassium chloride,

26. ## physics

An accelerating voltage of 2.46 * 10^3 V is applied to an electron gun, producing a beam of electrons originally traveling horizontally north in vacuum toward the center of a viewing screen 34.0 cm away. What is the magnitude of the deflection on the

27. ## Algebra

A kite is tied to the ground. The rays from the sun hit the kite perpendicular to the kite string, casting a shadow of the kite on the ground. The coordinates in the diagram are given in feet. What is the distance from where the kite is tied to the shadow?

28. ## Algebra 1 HELP PLEASE!

suppose P equals {0,1,2,3,4,5,6,7,8,9} and V equals {2,4,6,8,10,12,14,16,18,20}. What is P (circle) V?

29. ## physics

Two very long, straight, parallel wires carry currents that are directed perpendicular. Wire 1 carries a current I1 into the page (in the -z direction) and passes through the x axis at x = +a. Wire 2 passes through the x axis at x = -2a and carries an

30. ## Geometry

A gardener wants the three rosebushes in her garden to be watered by a rotating water sprinkler. The gardener draws a diagram of the garden using a grid in which each unit represents 1 ft. The rosebushes are at (1, 3), (5, 11), and (11, 4). She wants to

31. ## calculus

Let P= (V^2)R / (R+r)^2 Calculate dP/dr, assuming that r is variable and R is constant.

32. ## physics conservation of momentum

A 0.5 kg ball is thrown horizontally towards a wall with a speed of 10 m/s. The initial velocity is chosen to be the positive x-direction for this question. The ball horizontally rebounds back from the wall with a speed of 10 m/s in the negative

33. ## science

Four racecars are driving at constant speeds around a circular racetrack. The data table gives the speed of each car and each car’s distance from the center of the track at one instant. Car Speed (m/s) Position (m) A 40 20 B 40 25 C 50 20 D 50 25 Rank

34. ## chemistry

how many atoms of each element are present in five formula units of calcium permanganate?

86. ## Forensics

Strontium-90 is a radioactive waste product from nuclear reactors. It has a half life of 29 years. How many years would it take for a quantity of strontium-90 to decay 1/16 of its original mass?

87. ## Chemistry

Fish breathe the dissolved air in water through their gills. Assuming the partial pressures of oxygen and nitrogen in the air are to be .20 atm and .80 atm respectively, calculate the mole fractions of oxygen and nitrogen in the air dissolved in water at

88. ## Physics

A small m = 2.00 g plastic ball is suspended by a L = 24.0 cm long string in a uniform electric field, as shown in Figure P15.50. If the ball is in equilibrium when the string makes a 18.0° angle with the vertical as indicated, what is the net charge on

89. ## Physics

A pilot of mass 65 kg in a jet aircraft makes a complete vertical circle in mid-air. The vertical circle has a radius of 1.70 km at a constant speed of 215 m/s. Determine the force of the seat on the pilot at (a) the bottom of the loop and (b) the top of

90. ## Geometry

Complete two column proof. Given: x/6+2=15 Prove: x=78 x/6+2=15 A:______ x/6=13 B:______ x=78 C:_______ A:a. Given b. Subtraction Property of Equality c. Division Property of Equality B:a. Given b. Addition Property of Equality c. Multiplication Property

I have a question about the short story "Son" by John Updike. I have research this and read it but find it very confusing-I have two answers totally eliminated and would just like some input-Thank you so much Is "Son told in a.order from the contemporary

92. ## chem

A hot air balloon is filled with 1.51 × 106 L of an ideal gas on a cool morning (11 °C). The air is heated to 103 °C. What is the volume of the air in the balloon after it is heated? Assume that none of the gas escapes from the balloon.

93. ## chemistry

a fish tank holds 35 gallons of water. how many pounds of water are in the fish tank?

94. ## biology

What environmental conditions would favor sexual reproduction? What environmental conditions would favor asexual reproduction? Organism - sexual reproduction - gonads asexual reproduction - honeybees - Is pillbugs an asexually organism or is a sexually

95. ## phyics

A car takes 11 s to go from v=0m/s to v = 22 m/s at constant acceleration. If you wish to find the distance traveled using the equation d=1/2at2, what value should you use for a? Please help on this i don't know what i should put i think m/s squared but i

96. ## Calculus

Line l is tangent to the graph of y= x - x²/500 at point Q & it crosses the y-axis at (0, 20) a). Find the x-coordinate of point Q b. Write an equation for line l c) Suppose the graph of y=x-x^2/500, where x and y are measured in feet, represents a hill.

97. ## chem

A 455-g chunk of iron is removed from an oven and plunged into 385g water in an insulated container. The temperature of the water increases from 27 degrees celsius to 89 degrees celsius. If the specific heat of iron is 0.449 J g^-1 degrees Celsius^-1, what