# 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)

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...
3. ### 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...
4. ### 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...
5. ### 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...
6. ### 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...
7. ### 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...
8. ### 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) ↔...
9. ### 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...
10. ### 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 +...
11. ### 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...
12. ### 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...
13. ### 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} =...
14. ### 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 -...
15. ### 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...
16. ### 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...
17. ### Mass of block given μK and Force?

Homework Statement A student pushes a block with 240 N of force across a horizontal surface with a coefficient of kinetic friction of 0.4. The block accelerates at a rate of 0.88 m/s2. Find the mass of the block. Homework Equations μK = FK / FN F=ma The Attempt at a Solution...
18. ### Final velocity of this hockey puck

Homework Statement In the last second of a hockey game, a player slaps the puck in the empty net 32.5 m away. The puck leaves the stick with the speed of 41.5 m/s. Calculate the final velocity of the puck if its mass is 0.17 kg. Homework Equations μK = 0.005 μK = FK / FN F = ma v22 = v12...
19. ### Finding mass of this car

Homework Statement Each of the four wheels of a car pushes on the road with a force of 4.0 x 103 N [down]. The driving force on the car is 8.0 x 103 N [west]. The frictional resistance on the car is 6.0 x 103 N [east]. Calculate the mass of the car. Homework Equations F = ma Fnet = F1 +...
20. ### Does force normal change when you push an object at an angle?

Homework Statement You exert a force of 131 N [30° below horizontal] onto a 12.6 kg lawn mower, What is the force of gravity and normal force on the lawn mower? Homework Equations Fg= m × g FA (y component) = Sin30° × FA The Attempt at a Solution The force of gravity is equal to the force...
21. ### Finding volume of a solution using %W/V

Homework Statement What volume of a 30% W/V hydrogen peroxide solution is required to prepare 425 mL of a 6.0% W/V solution? Homework Equations %w/v = (weight solute/volume solution) x 100% The Attempt at a Solution I'm not quite sure what to do because here I am given 2 percentages...
22. ### Force required to pull trunk across floor

Homework Statement You are dragging a 110 kg trunk across a floor at a constant velocity with horizontal force of 380 N. A friend decides to help by pulling on the trunk with a force of 150 N [up]. Will this help? Calculate the force required to pull the trunk at a constant velocity to help...
23. ### Magnitude of frictional force during terminal velocity

Homework Statement A parachutist, after jumping from the plane, is accelerating down with average acceleration of 1.6 m/s2 (relative to the ground). What is the force of friction slowing his motion is mass of the parachutist with his equipment is 124 kg? What is the frictional force when the...