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    Lenses with eyes

    The focal length of a relaxed human eye is approximately 1.78 cm. When we focus our eyes on a close-up object, we can change the refractive power of the eye by about 16 diopters. Calculate the focal length of the eye when we focus closely. 1/di+1/do=1/f im not really sure what to...
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    Lens optics

    A typical red blood cell subtends an angle of only 1.90E-5 rad when viewed at a person's near-point distance of 25.0 cm. Suppose a red blood cell is examined with a compound microscope in which the objective and eyepiece are separated by a distance of 12.5 cm. Given that the focal length of the...
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    Camera Lens Problem

    The actual frame size of "35-mm" film is 24 mm x 36 mm. You want to take a photograph of your friend, who is 1.70 m tall. Your camera has a 60.0 mm focal length lens. How far from the camera should your friend stand in order to produce a 36.0 mm-tall image on the film? i thought you would...
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    Combination Lens problem

    A converging lens of focal length 7.94 cm is 19.7 cm to the left of a diverging lens of focal -6.04 cm. A coin is placed 12.2 cm to the left of the converging lens. A) Calculate the location of the coins final image. B)Calculate the magnification of the coin's final imag. The equation i...
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    Finding magnitude of gravitational force?

    The masses and coordinates of three spheres are as follows: 16 kg, x = 0.75 m, y = 3.00 m; 34 kg, x = -2.50 m, y = -2.75 m; 60 kg, x = 0.00 m, y= -0.75 m. What is the magnitude of the gravitational force on a 30 kg sphere located at the origin due to the other spheres? Homework Equations i...
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    Rearranging acceleration equations

    Starting from the constant-acceleration kinematic equations, write a formula that gives t in terms of xi, xf, vi, and vf. do i solve for acceleration in a equation and then plug it in? Starting from the constant-acceleration kinematic equations, write a formula that gives vf in terms...
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    Maximum height of an object

    A model rocket is launched straight upward with an initial speed of 54.4 m/s. It accelerates with a constant upward acceleration of 2.20 m/s2 until its engines stop at an altitude of 131 m. What is the maximum height reached by the rocket? How long after lift off does the rocket reach its...
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    Motion please help!

    A roller coaster moves 201 ft horizontally, then rises 150 ft at an angle of 27.5o above the horizontal. It then travels 150 ft at an angle of 38.2o below the horizontal. What is the magnitude of its displacement from the starting point at the end of this movement? What is the angle relative to...
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    Kinematics Problem on hot air balloon

    A hot air balloon has just lifted off and is rising at the constant rate of 1.30 m/s. Suddenly, one of the passengers realizes she has left her camera on the ground. A friend picks it up and tosses it straight upward with an initial speed of 9.40 m/s. If the passenger is 2.30 m above her friend...
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