# Search results

1. ### Trying to find the amount of stretch of a spring for a launch

Homework Statement I'm doing an experiment where I have to calculate the stretch of a spring needed for it to launch itself into a trashcan located some distance away. The spring is located on the edge of a ramp that is 1.13 m high. The angle of the ramp is 30 degrees above horizontal. The...
2. ### Galilean transformation problem (Speed)

Why wouldn't it be +126 m if she is moving forward?
3. ### Galilean transformation problem (Speed)

Homework Statement A girl is riding a bicycle along a straight road at constant speed, and passes a friend standing at a bus stop (event #1). At a time of 60 s later the friend catches a bus (event #2) If the distance separating the events is 126 m in the frame of the girl on the bicycle...
4. ### A pulley system with two objects stacked on each other

no when you add the 3 equations together you only have 2 unknowns. Then if you find the acceleration (7.35) and solve for mC you get 39 kg, which seems to be the correct answer.
5. ### A pulley system with two objects stacked on each other

Homework Statement Block B, with mass 5.00kg, rests on block A, with mass 8.00kg , which in turn is on a horizontal tabletop. There is no friction between block A and the tabletop, but the coefficient of static friction between block A and block B is 0.750. A light string attached to block A...
6. ### Finding the time when two stones cross paths

##D_A + 6.69 = D_B## It took me a while, but I finally found meaning behind this equation... displacement of rock A: ##D_A = -6.69 m [up]##, and B: ##D_B = 0 m.## -6.69 + 6.69 = 0, brilliant!
7. ### Finding the time when two stones cross paths

Homework Statement Two stones are thrown simultaneously, one straight upward from the base of a cliff and the other straight downward from the top of the cliff. The height of the cliff is 6.69 m. The stones are thrown with the same speed of 9.97 m/s. After what time do the stones cross paths...
8. ### Average Speed vs. Instantaneous Speed

you are right
9. ### How do you do analysis of units?

Homework Statement Show the unit analysis of this equation that relates frequency to length (in centimeters) of a pendulum f = 5.1L^{-0.5} Homework Equations f = \frac{1}{2\pi\sqrt{\frac{L}{g}}} ? The Attempt at a Solution I cannot find much info about this online, but I gave it a go: f...
10. ### Relationship between frequency and length of pendulum

Homework Statement We calculated times of the periods of varying pendulum lengths. (20cm, 40cm, 60cm, 80cm). Then the frequency was calculated for each length and then a frequency-length graph was made. Since the graph is an exponential relationship we graphed our values on a log-log chart...
11. ### Height when a ball is thrown vertically at half its velocity

I didn't fully understand what you mean
12. ### Height when a ball is thrown vertically at half its velocity

Homework Statement A baseball is thrown vertically into the air with a velocity, v, and reaches a maximum height, h. At what height was the baseball with one-half its original velocity? Assume no air resistance. Homework Equations v22 = v12 + 2ad ? The Attempt at a Solution let...
13. ### Solubility Product, finding molar concentration

So the only situation the 2:1 ratio applies is if I was trying to find moles?
14. ### Solubility Product, finding molar concentration

Homework Statement If the 2.0 x 10-5 mol of Cu(IO3)2 can dissolve in 2 L of NaIO3, find the molar concentration of the NaIO3 solution. Ksp = 1.4 x 10-7 for Cu(IO3)2. Homework Equations The Attempt at a Solution Let y = [IO3-(aq)] present in the solution from NaIO3 Cu(IO3)2(s) ↔...
15. ### PH for this Weak Acid-Strong Base titration.

0.029+x? Oh I see H_{}C_{2}H_{3}O_{2} + H_{2}O \leftrightharpoons H_{3}O + C_{2}H_{3}O_{2}^{-} I \:\: 0.043 \:\:\:\:\:\: - \:\:\:\:\:\:\:\:\:\:\:\: 0 \:\:\:\:\:\:\:\:\:\:\:\: 0.029 C \:\:\:\:\:\: -x...
16. ### PH for this Weak Acid-Strong Base titration.

Thanks for the reply. The other approach is where they use a mole chart like this I just want to know the situations of when to use a mole chart. This had been confusing me for weeks haha.
17. ### PH for this Weak Acid-Strong Base titration.

\:Homework Statement What is the pH when 10 ml of 0.1 M NaOH is added to 25 ml of 0.1 M H_{}C_{2}H_{3}O_{2}? Homework Equations pH = -log[H_{3}O] The Attempt at a Solution The main thing confusing me about this type of problem is that my teacher taught me a way which is different from the...
18. ### If cosθ = -5/13 and 0 <= θ <= 2π, what are possible values of θ?

Homework Statement If cosθ = -5/13 and 0 <= θ <= 2π, what are possible values of θ? Homework Equations The Attempt at a Solution θ is in quadrant 2 or 3 in quadrant 2: related acute = cos^{-1}(5/13) = 1.18 θ = π - 1.18 = 1.96 radians in quadrant 3: related acute angle = 1.18 θ = π +...
19. ### Finding the radian value of this angle which passes through a point

Homework Statement The terminal arm of an angle in standard position passes through (-7,8). Find the radian value of the angle in the interval [0,2∏], to the nearest hundredth. Homework Equations sinθ = \frac{y}{r} cosθ = \frac{x}{r} tanθ = \frac{y}{x} The Attempt at a Solution The terminal...
20. ### Getting N-methyl-2-aminobutane from 2-aminobutane

Homework Statement draw structural equation for going from 2-aminobutane to N-methyl-2-aminobutane Homework Equations The Attempt at a Solution CH3=CH-CH2-CH3 + CH4 ----> CH3-CH-CH2-CH3 | | NH2 CH3-NH2 It...
21. ### Finding explicit formula of this recursion formula

is that calculus? :\$
22. ### Finding explicit formula of this recursion formula

Homework Statement Write an explicit formula for the sequence determined by the following recursion formula. t_{1}= 0; t_{n} = t_{n-1} + \frac{2}{n(n+1)} The Attempt at a Solution t_{1} = 0 t_{2} = t_{1} + \frac{2}{2(2+1)} t_{2} = \frac{1}{3} t_{3} = t_{2} + \frac{2}{3(3+1)} t_{3} =...
23. ### Proving This Trigonometric Identity

=\frac{1+cosx}{1-cosx} =\frac{1+cosx}{1-cosx} × \frac{1+cosx}{1+cosx} = \frac{1+2cosx + cos^2x}{1-cos^2x} =\frac{1+2cosx+cos^2x}{sin^2x} thanks guys
24. ### Proving This Trigonometric Identity

1. Prove: \frac{cscx +cotx}{cscx-cotx} = \frac{1+2cosx+cos^2x}{sin^2x} Homework Equations tanx = \frac{sinx}{cosx} cotx = \frac{cosx}{sinx} cscx secx cotx sin^2x + cos^2x = 1 The Attempt at a Solution Left side: =\frac{cscx +cotx}{cscx-cotx} =\frac{1/sinx + cosx / sinx}{1/sinx -...
25. ### Domain and Range of this function

Ah so when x = ±2, it is undefined. So... domain: {x∈R | x ≠ ±2} What do I do for range? when i plug it in i get undefined?
26. ### Domain and Range of this function

Homework Statement What is the domain and range of the function y = \frac{2}{x^2-4} The Attempt at a Solution I'm lost, and I noticed it seems like a difference of squares so what I did is y = \frac{2}{(x-2)(x+2)}. So the x value of vertex is 0. And i subbed this into the equation...
27. ### Some confusion with c1v1 = c2v2

Homework Statement Determine how much distilled water must be added to 250 ml of a 1.5 M solution of Na2CO3 to dilute it to a concentraion of 0.5 M. Homework Equations c1v1=c2v2 The Attempt at a Solution I'm having trouble understanding how to identify c1,v1,c2, and v2, especially since...
28. ### Mass of block given μK and Force?

Fnet = 240 - (0.4 x 9.8m) = 240 - 3.92m 240 - 3.92m = 0.88m 240 = 0.88m + 3.92m 240 = 4.8m m = 50 kg wohooooooo thanks a lot!:biggrin:
29. ### Mass of block given μK and Force?

240 - 2.92m = 0.88m 240 = 0.88m + 2.92m 240 = 3.8m m = 63 kg
30. ### Mass of block given μK and Force?

oh wow my bad... Fnet = 240 - (0.4 x 9.8m) = 240 - 2.92m Still don't get what I need to do next?