Physics

A mechanical system is used to pull a tarp over a grass tenniscourt. On a clear, sunny day, the efficiency of the system is55%. After a rainstorm, the efficiency is measured to be 65%.Explain why there is a difference in the efficiencies.
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Two balloons are separated by a distance of 25. 5 cm. One balloon is charged with a charge of + 6. 25 nC = + 6. 25 x 10-9 C and the other balloon is charges with a charge of - 3. 5 nC = - 3. 5 x 10-9 C. Calculate the magnitude of Coulombic Force between them. Explain what kind of coulombic force will exist between them (attractive or repulsive)?
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Calculate the intensity transmission coefficient TI and reflection coefficient RI for the following interfaces: muscle/kidney, air/ muscle, bone/ muscle. assuming that the ultrasound incidence beam makes angle of 30 degree
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You look up and see a helicopter pass directly overhead. 3. 10s later you hear thesound of the engine. If the air temperature is 23. 0C, how high was the helicopterflying?
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according to the laws of thermal radiation, hotter objects emit photons with group of answer choices a lower average energy. a lower average frequency. a shorter average wavelength. a higher average speed.
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What's the mass and weight of each of object if there were placed on mass gmars=3. 8n/kg
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The force of __________ will be greater if one object has a larger mass than the other
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Sean throws a baseball at an angle of 25 relative to the ground at a speed of 23m/s. What is the maximum height the ball will achieve? How long will it be in the air? How far away does Kelly need to be to catch the ball?
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one person pulls on a rope with a force of 400 n to the right. another person pulls on the opposite end with a force of 600 n to the left. what is the unbalanced net force?
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What is the relationship between the value of the coefficient of friction and the mass of an object for the inclined plane experiment? to what extend does the result confirm this?
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ACTIVITY 1: AGREE OR DISAGREEWrite AGREE, if you think the statement is correct and DISAGREE if otherwise1. An RPE of 10 means that the activity is very light2. Swimming and playing basketball are vigorous activities3. Street and hip hip dances are active recreational activities4. Proper execution of dance steps increases the risk of injuries5. A normal nutritional status means that weight is proportional to the height6. Physical inactivity and unhealthy diet are risk factors for heart disease. 7. Risk walking and dancing are activities which are moderate intensity8. One can help the community by sharing his/her knowledge and skills in dancing9. Surfing on the internet and playing computer games greatly improve one's fitness10. A physically active person engages in 5-10 minutes of moderately vigorous physical activity three or moretimes a week
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The second law of thermodynamics states thata change in a system's energy is equal to the energytransferred to the system.energy cannot be created or destroyed.energy can flow from a colder object to a warmer objectonly if something does work.the only way to reduce an object's temperature is toincrease the entropy of the environment.
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How many grams are in 0. 02mol of Mg (25. 3g/mol)
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A crate (60 kg) is in an elevator traveling upward and slowing down at 6 m/s2. find the normal force exerted on the crate by the elevator. assume g
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An archer shot a 0. 04 kg arrow at a target. The arrow accelerated at 7,000 m/s2 to reach a speed of 60. 0 m/s as it left the bow. How much force did the arrow have? ___N
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Robert and his younger brother Jake decide to go fishing in a nearby lake. Just before they cast off, they are both sitting at the back of the boat and the bow of the boat is touching the pier. Robert notices that they have left the fishing bait on the pier and asks Jake to go get the bait. Jake has a mass of 59. 5 kg and an arm reach of 50. 0 cm, Robert has a mass of 87. 5 kg, and the boat has a mass of 83. 0 kg and is 2. 70 m long. Determine the distance the boat moves away from the pier as Jake walks to the front of th
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20. An astronaut weighs 8.00 102newtons on thesurface of Earth. What is the weight of the astronaut6.37 106meters above the surface of Earth?
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A weightlifter lifts a 13.0-kg barbell from the ground and moves it a distance of 1.30 meters upwards. what is the work she does on the barbell? roundyour answer to a whole number. hint mass x gravity is the weight of the barbell
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Consider an atom that has an electron in an excited state. The electron falls to a lower energy level. What effect does that have on the electron?A. The electron releases energy in the form of light.B. The electron absorbs energy in the form of light.The electron retains its energy without any change.D. The electron transfers its energy to other electrons.
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How does writing work according to Newton's 3rd Law?
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An astronaut weighs 8.00 102newtons on thesurface of Earth. What is the weight of the astronaut6.37 106meters above the surface of Earth?
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convert 750W into kilowatts
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A cheetah has 5 joules of kinetic energy and runs up a 5 m hill. When it gets to the top of the hill, it stops. What is the gravitational potential energy of the cheetah?
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The farthest bright galaxies that modern telescopes are capable of seeing are up to:.
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