Category: General Physics
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Colliding Balls
Balls A and B roll across a table, then collide and bounce off each other. The paths of the two balls are pictured (viewed from above) in the diagram. A) Which set of arrows best represents the change in momentum for balls A and B? => C B) Which of the following arrows indicates…
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Conservation of Energy Ranking Task
Six pendulums of various masses m are released from various heights h above a tabletop, as shown in the figures below. All the pendulums have the same length and are mounted such that at the vertical position their lowest points are the height of the tabletop and just do not strike the tabletop when released. Assume that…
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All Work and No Play
Learning Goal: To be able to calculate work done by a constant force directed at different angles relative to displacement If an object undergoes displacement while being acted upon by a force (or several forces), it is said that work is being done on the object. If the object is moving in a straight line and the displacement…
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Time Elapse
The back wall of an auditorium is 28.0 m from the stage. If you are seated in the middle row, how much time elapses between a sound from the stage reaching your ear directly and the same sound reaching your ear after reflecting from the back wall? The speed of sound in the air is 343 m/s.…
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What is its frequency?
A sinusoidal wave travels with speed 250 m/s. Its wavelength is 4.0 m. What is its frequency? v = 190 m/s λ = 30 m f= v/λ f= 190/3 =63.33
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Wavelength and Speed
The displacement of a wave traveling in the positive x-direction isy(x, t) = (3.5 cm) cos(2.7x – 92t), where x is in m and t is in s. v = 190 m/s λ= 3.0 m f = ? v=fλ f = v/λ f= 190/3 = 63.33 Displacement is y(n, t) = (3.5 cm) cos(2.7x – 92t) x =…
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Amplitude, Wavelength, and Frequency
The figure is a history graph at x = 0 m of a wave moving to the right at 2 m/s. What is the amplitude of this wave? A = How high it goes = 6cm What is the frequency of this wave? T = .6 F= 1/.6 = 1.66 = 1.7 Hz =2 Hz What…
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Frequency of Electromagnetic Wave
What is the wavelength of a 2.4 MHz ultrasound wave traveling through aluminum? Assume that the speed of sound in aluminum is 5100 m/s. frequency = 2.4 Mhz = 2400000hz v = 5100 m/s λ = v/f 5100/2400000 = .002125 m = 2.212500 mm What frequency of electromagnetic wave would have the same wavelength as the ultrasound…
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How Many Joules of Solar Energy?
The intensity of electromagnetic waves from the sun is 1.4 KW/m2 just above the earth’s atmosphere. Eighty percent of this reaches the surface at noon on a clear summer day. Suppose you model your back as a 33 cm x 53 cm rectangle. How many joules of solar energy fall on your back as you work on your tan for 1.4 h?…
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What is the Frequency?
A friend of yours is loudly singing a single note at 400 Hz while racing toward you at 25.5 m/s on a day when the speed of sound is 340 m/s. What frequency do you hear? = (346/346-24.6) 380 = 346 x 380/ 321.4 = 409.085 = 409 hz