Recent content by michaelplease

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    Difficult 2D Kinematics Question

    I must have typed something wrong into my calculator. vo = 7.48 m/s Thanks so much for your help!
  2. M

    Difficult 2D Kinematics Question

    vfy is negative if we say that positive y is up. so I combined a = -vfy and vfy = b-gt -> a = gt - b gt - b = 4.5/t 4.5 = gt^2 - bt add to 2nd equation listed : 5.5 = gt^2 - 4.905 t^2 t = 1.06 s Is that right? Then by equation 1: a = 4.25 m/s By equation 3: b = 6.15 m/s and vo = 26.2 m/s...
  3. M

    Difficult 2D Kinematics Question

    Oh yes, I forgot to write that one. vfy = b-gt I am still stuck though trying to solve these equations (despite having so many!) Do you mind showing me how to do the algebra?
  4. M

    Difficult 2D Kinematics Question

    Homework Statement A basketball is thrown from a height of 2m. The direction of its velocity when it hits the rim of the basketball hoop is 45 degrees below the horizontal. The basketball hoop is 3m above the ground and 4.5 m in front of the shooter. How long does the ball take to hit the rim...
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    How Does Efficiency Loss Affect Voltage and Current in a Transformer?

    Homework Statement A step-down transformer going from 240 V to 12 V is 95% efficient. The input current is 20 A. a) Determine the primary turns: secondary turns ratio necessary in order to maintain a 12V output. b) Determine the output current. I have solved it as if I needed an secondary...
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    Kinetic/Potential Energy Change in an Exothermic Reaction

    I am having trouble understanding what exactly happens in an exothermic reaction. Specifically, I need to answer the following question: In an exothermic reaction: a) the kinetic energy increases and the potential energy decreases. b) the kinetic energy and the potential energy decrease...
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    Significant Figures in Average Velocity Calculation

    Homework Statement A rocket traveling at 88 m/s is accelerated uniformly to 132 m/s over a 15.0 second interval. What is its average velocity, with the correct number of significant figures? An object traveling at 11.5 m/s is decelerated uniformly to 4.5 m/s. What is its average velocity...
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