# Posts by Rin

Total # Posts: 17

**Physics Please **

A boy on a swing is pulled to a position 2.34 m off the ground and released. At the fastest and lowest point of the swing the boy is 0.50 m off the ground and travelling 3 m/s. The percent efficiency of this swing system is?

**Math**

The sum of two acute angles in a right triangle is 90 degrees. Find the acute angles on the right triangel wherein twice the first is 40 degrees more than thrice the second

**Math**

The length of the rectangle 5cm more than twice the width.The perimeter is 70.What is the area?

**Physics**

A 47.0-g Super Ball traveling at 29.5 m/s bounces off a brick wall and rebounds at 15.5 m/s. A high-speed camera records this event. If the ball is in contact with the wall for 5.00 ms, what is the magnitude of the average acceleration of the ball during this time interval?

**Math**

The maximum number of arbitrary constants is equal to a. Number of derivatives in the differential equation b. Degree of differential equation c. Order of differential equation e. None of the above I don't understand this, but my guess it's letter A. Please help.

**Physics - please check my answer**

A man tosses a ball upward. It reaches its highest point after 25 seconds. Find its initial velocity. Alright, so I tried solving this. I used the equations (let v = initial velocity): h = v^2 / 2g , and h = (v*t) - (1/2)(g)(t^2) and I got 101.48 m/s. Is this correct?

**physics**

Does increasing the force affect the amount of work done climbing the stairs? Does increasing the distance affect the amount of work done climbing the stairs? How would you describe the mathematical relationship between these two parameters

**physics**

1.A beam of light passes through the air and enters a diamond at an angle of incidence of 40 degrees. Use Snell’s Law to find the angle of refraction of the diamond. (Index of refraction for air is 1.00 and the index of refraction of a diamond is 2.42.) If the beam of ...

**Biochemisty**

The DNA alpha-helix structure has 566900 complete turns. The average molar mass of one base pair of nucleotides in DNA is approximately 469 g/mol. If the spacing between successive base pairs is about 0.69 nm, and a complete turn in the helical structure of DNA occurs every 6....

**Physical Science**

17. Based on the chemical equation, the reaction is endothermic. Increasing the temperature will favor the forward (left to right) reaction. Or you may think of the heat as one of the reactants. If you increase heat, then the amount of products will also increase. Otherwise, ...

**Calculus - please help!**

How do you do this? Find the volume generated by revolving the area bounded by the ellipse(x^2)/9 + (y^2)/4 = 1 about the line x=3.

**math**

A function f(x) has domain [0,25), range (-∞,5], and intercepts (2,0), i(17,0), 0,9). A function h(x) has domain (-∞,16), range (-∞,42) and intercepts (3,0), (0,-10). Find the domain of each of the following. 1. f + h 2 f/g 3. f*g

**algebra-trig help asap**

The 2 unequal side if a parallelogram measure 4.8 inches and 8.3 inches, respectively. If the longer diagonal measure is 11.2 inches, find the lenght of the shorter diagonal.

**trig**

By expressing 3x as (2x + x) prove that cos3x = 4cos^3x - 3cosx

**trig**

By expressing 3x as (2x + x) prove that cos3x = 4cos^3x - 3cosx

**MATH**

The eaves of a roof sloping at 23° overhand the walls, the edge of the roof being 75 cm from the top of the wall. The top of the wall is 5.4 metres above the ground. What is the height above the ground of the edge of the roof, to the nearest centimeter?

**Math-approximation with fractions:7th grade math**

yeah this is sooooo hard, does anyone understand? I got to do this for problems 14.-19. Its 7th grade math work page 4.5 Anyone got the same?

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