Most popular questions and responses by micole

    I am struggling with organizing stoichiometry problems; I know how to solve them after they're set up. Here is an example: "An organic compound with a FW of 417 was analyzed for ethoxyl {CH3-CH2O-} groups with the rxn: ROCH2CH3 + HI --> ROH +CH3CH2I

    asked on May 16, 2008
  2. physics

    A 64.0 kg person stands on a lightweight diving board supported by two pillars, one at the end of the board, the other 1.20 m away from the end. The pillar at the end of the board exerts a downward force of 829 N. How far from the pillar at the end of the

    asked on May 31, 2007
  3. Physics

    Two point charges lie on the x axis. A charge of + 6.5 µC is at the origin, and a charge of -1.5 µC is at x = 10.0 cm. What is the net electric field at x = -2.0 cm? I found the electrical field for each charge using the equation E= k(q)/ r^2. My

    asked on July 7, 2007
  4. physics

    A football is thrown horizontally with an initial velocity of (16.5 m/s). Ignoring air resistance, the average acceleration of the football over any period of time is (-9.81 m/s2). (a) Find the velocity vector of the ball 1.62 s after it is thrown. (b)

    asked on May 14, 2007
  5. physics

    At a recent rock concert, a dB meter registered 112 dB when placed 1.70 m in front of a loudspeaker on the stage. (a) What was the power output of the speaker, assuming a hemispherical radiation of the sound and neglecting absorption in the air? (b) How

    asked on June 18, 2007
  6. physics

    Seatbelts provide two main advantages in a car accident: (i) they keep you from being thrown from the car, and (ii) they reduce the force that acts on you during the collision to survivable levels. The second benefit can be illustrated by comparing the net

    asked on May 17, 2007
  7. physics

    A person is to be released from rest on a swing pulled away from the vertical by an angle of 15.8°. The two frayed ropes of the swing are 2.75 m long, and will break if the tension in either of them exceeds 350 N. What is the maximum weight the person can

    asked on May 24, 2007
  8. physics

    You are riding on a jet ski at an angle upstream on a river flowing with a speed of 2.8 m/s. Suppose the jet ski is moving at a speed of 18 m/s relative to the water. (a) At what angle must you point the jet ski if your velocity relative to the ground is

    asked on May 14, 2007
  9. physics

    An explosion breaks an object into two pieces, one of which has 3.20 times the mass of the other. If 8000 J were released in the explosion, how much kinetic energy did each piece acquire? I started with using KE = (1/2)mv^2 and m1v1 = m2v2. Then

    asked on May 29, 2007
  10. physics

    A 85 kg trampoline artist jumps vertically upward from the top of a platform with a speed of 3.5 m/s. How fast is he going as he lands on the trampoline, 3.0 m below? If the trampoline behaves like a spring of spring constant 5.2 x 10^4 N/m, how far does

    asked on May 28, 2007
  11. Physics

    A neutron collides elastically with a helium nucleus (at rest initially) whose mass is four times that of the neutron. The helium nucleus is observed to rebound at an angle '2 = 41° from the neutron's initial direction. The neutron's initial speed is 5.6

    asked on May 30, 2007
  12. physics

    A car is behind a truck going 23.0 m/s on the highway. The driver looks for an opportunity to pass, guessing that his car can accelerate at 2.2 m/s2, and he gauges that he has to cover the 24.0 m length of the truck, plus 10 m clear room at the rear of the

    asked on May 13, 2007
  13. physics

    A block of mass m1 = 4.50 kg sits on top of a second block of mass m2 = 13.9 kg, which in turn is on a horizontal table. The coefficients of friction between the two blocks are µs = 0.300 and µk = 0.100. The coefficients of friction between the lower

    asked on May 21, 2007
  14. physics

    A football is thrown horizontally with an initial velocity of (16.5 m/s). Ignoring air resistance, the average acceleration of the football over any period of time is (-9.81 m/s2). Find the magnitude and direction of the velocity at this time and direction

    asked on May 15, 2007
  15. physics

    A Coast Guard cutter detects an unidentified ship at a distance of 18 km in the direction 16.2° east of north. The ship is traveling at 22.5 km/h on a course at 36.2° east of north. The Coast Guard wishes to send a speedboat to intercept the vessel and

    asked on May 16, 2007
  16. physics

    A 2.0kg box rests on a plank that is inclined at an angle of 65° above the horizontal. The upper end of the box is attached to a spring with a force constant of 25 N/m. If the coefficient of static friction between the box and the plank is 0.17, what is

    asked on May 21, 2007
  17. physics

    A firefighter at street-level, 55.0 m away from a burning building, directs a stream of water from a fire hose at an angle of 35.0° above the horizontal. If the speed of the stream is 50.0 m/s, at what height will the stream of water strike the building?

    asked on May 16, 2007
  18. chemistry

    We're studying acids and bases; the question states that 50mL of 0.1M HNO3 solution is mixed with 25mL of 0.1M NaOH. What is the pH? I thought that I would use the Henderson-Hasselbach equation; but my answer does not match the one give in the solution.

    asked on May 23, 2008
  19. Chemistry

    If you have a list of acids or bases and their conjugate salts, and are asked which pairs create the best buffer, how would you know which are best?

    asked on June 24, 2008
  20. physics

    A ball is tossed from an upper-story window of a building. The ball is given an initial velocity of 9.50 m/s at an angle of 24.0° below the horizontal. It strikes the ground 5.00 s later. (a) How far horizontally from the base of the building does the

    asked on May 16, 2007
  21. physics

    A ball is thrown upward from the top of a 27.0-m-tall building. The ball's initial speed is 12 m/s. At the same instant, a person is running on the ground at a distance of 31.2 m from the building. What must be the average speed of the person if he is to

    asked on May 13, 2007
  22. physics

    Driving along a crowded freeway, you notice that it takes a time t to go from one mile marker to the next. When you increase your speed by 4.0 mi/h, the time to go one mile decreases by 11 s. What was your original speed? I used the equation V=d/t; I

    asked on May 13, 2007
  23. math

    i am between 21 and 34 you say name when you count by fives from zero

    asked on December 17, 2013