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Questions 1,148
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A baker uses oven mitts to open an oven, take a loaf of bread out, and place it on a plate. In 3–4 sentences, identify three examples of thermal energy transfer in the scenario.(4 points)
1 answer
A pot of water is being heated on the stovetop. The water molecules closest to the burner rise in the pot when they gain thermal energy. In 1–2 sentences, explain why the water rises.(2 points)
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When thermal energy is applied to ice, the ice’s temperature rises until 0°C and then stays the same for a period of time. In 1–2 sentences, explain why this takes place.(2 points)
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In 1–2 sentences, describe the relationship between heat and thermal insulators.(2 points)
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What happens when a cold spoon is placed in hot soup?(1 point) The spoon’s molecules have less kinetic energy, so they transfer thermal energy to the soup. The soup’s molecules have the same kinetic energy as the spoon’s...
1 answer
How does a heater in one corner of a fish aquarium warm the whole aquarium?(1 point) The heater adds thermal energy evenly to the aquarium’s water. The heater warms the air above the aquarium, which warms the water. The...
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What is the best description of the conclusion of a scientific investigation?(1 point) The conclusion states that the results are correct. The conclusion uses reasoning to explain and interpret the results. The conclusio...
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Which scenario best describes a scientist who is studying thermal energy?(1 point) She works with a team, telling each member exactly what to do. She works on a team, with each member carrying out all of the same tasks t...
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Why does an ice cube melt even in a cold glass of water?(1 point) The ice cube is still colder than the water, so thermal energy moves from the ice cube to the water. The air around the water melts the ice cube. Ice cube...
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What happens when thermal energy is applied to an ice cube? (1 point) Its water molecules lose potential energy. Its water molecules lose kinetic energy, so the ice cube melts. Its water molecules gain kinetic energy and...
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What do you measure when you find a substance’s temperature?(1 point) average kinetic energy of the particles in the substance potential energy of the substance kinetic energy of the substance absolute heat of the substa...
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How can a stationary metal sphere have kinetic energy, the energy of motion?(1 point) The metal is made of atoms, which store potential energy. The metal sphere can be rolled. The metal’s molecules are moving around. The...
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A uniform rod of mass 2.20 kg and length 2.00 m is capable of rotating about an axis passing through its center and perpendicular to its length. A mass m1 = 4.90 kg is attached to one end and a second mass m2 = 2.50 kg i...
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Calculate the rotational kinetic energy (in J) of Venus on its axis. (Assume its mass to be 4.90 ✕ 1024 kg, the period about its axis to be 5830 h, and its diameter to be 12100 km.) (b) What is the rotational kinetic ene...
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Calculate the angular momentum (in kg·m2/s) of an ice skater spinning at 6.00 rev/s given his moment of inertia is 0.390 kg·m2. (b) He reduces his rate of spin (his angular velocity) by extending his arms and increasing...
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While punting a football, a kicker rotates his leg about the hip joint. The moment of inertia of the leg is 3.54 kg · m2 and its rotational kinetic energy is 167 J. (a) What is the angular velocity of the leg? (Give your...
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Suppose you start an antique car by exerting a force of 460 N on its crank for 0.170 s. What angular momentum (in kg·m2/s) is given to the engine if the handle of the crank is 0.310 m from the pivot and the force is exer...
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A playground merry-go-round has a mass of 120 kg and a radius of 1.80 m and it is rotating with an angular velocity of 0.550 rev/s. What is its angular velocity (in rev/s) after a 18.0 kg child gets onto it by grabbing i...
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Three children are riding on the edge of a merry-go-round that is 202 kg, has a 1.60 m radius, and is spinning at 15.3 rpm. The children have masses of 17.4, 28.5, and 32.8 kg. If the child who has a mass of 32.8 kg move...
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What is the final velocity (in m/s) of a hoop that rolls without slipping down a 4.50-m-high hill, starting from rest?
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A ball with an initial velocity of 4.29 m/s rolls up a hill without slipping. (a) Treating the ball as a spherical shell, calculate the vertical height (in m) it reaches. (b) Repeat the calculation (in m) for the same ba...
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Consider a father pushing a child on a playground merry-go-round. The system has a moment of inertia of 84.4 kg · m2. The father exerts a force on the merry-go-round perpendicular to its 1.50 m radius to achieve a torque...
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Suppose you exert a force of 227 N tangential to a 0.255 m radius 75.0 kg grindstone (a solid disk). (Give your answers to at least 2 decimal places.) (a)What torque (in N · m) is exerted? (Enter the magnitude.) (b)What...
1 answer
Calculate the linear acceleration of a car, the 0.200-m radius tires of which have an angular acceleration of 13.0 rad/s2. Assume no slippage and give your answer in m/s2. (b)How many revolutions do the tires make in 2.5...
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Consider a father pushing a child on a playground merry-go-round. The system has a moment of inertia of 84.4 kg · m2. The father exerts a force on the merry-go-round perpendicular to its radius to achieve an angular acce...
1 answer

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Latest answers from t

How could randomization be used to select the two groups?
Answer on a public question
that is wrong
Answer on a public question