Master Physics with Fun Quizzes & Brain Teasers!

A child is standing in the center of a rotating platform and then walks toward the outside edge. Describe the change in the child-platform system, if any, of each of the following quantities. Justify your answers. Angular momentum Rotational inertia Angular velocity Rotational kinetic energy
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A frog of mass 0.5 kg jumps vertically upward with the initial velocity = (1.0 ms). Considering the highest point of the frog's jump, what are Pave (the average power exerted by gravity on the frog from the start of thejump to its highest point) and Pinst (the instantaneous power exerted by gravity on the frog at the highest point).Ignore air resistance and approximate g ~ 10 m/S?.(A) Pave = -2.5 W, Pinst = 0(B) Pave = 2.5 W, Pinst = 0(C) Pave = -5.0 W, Pirist = 0(D) Pave = - 2.5 W, Pinst = -5.0 WAnswer LOs:A: 14,21,32.33.33B: 14.33C: 14.33D: 21.33
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a 4.0 kgkg, 36-cmcm-diameter metal disk, initially at rest, can rotate on an axle along its axis. a steady 6.5 nn tangential force is applied to the edge of the disk.What is the disk's angular velocity in rpm 4.0 s later?
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Find the de Broglie wavelength of a baseball pitched at a speed of 44.6 m/s . Assume that the mass of the baseball is 0.143 kg.Express your answer in meters
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write an expression for how much of the ice mmelted has melted?
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If 1800J of heat are added to a 190-g object, its temperature increases by 10o C.A. What is the heat capacity of this object? C= ? kJ/oCB. What is the object's specific heat? c= ? kJ/(kg x K)
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if two currents are in opposing directions through a branch of a circuit, in what direction will the net current flow?
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when people visit the local tanning salon, they absorb photons of ultraviolet (uv) light to get the desired tan. what are the frequency and wavelength of a uv photon whose energy is 5.9 * 10-19 j?
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what is the mass of a 1.70- l l sample of a liquid that has a density of 0.921g/ml 0.921 g / m l
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if you have a circuit with one battery and one resistor and want to measure the current flowing through the resistor, how would you do it?
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based on scientist 2s discussion, an imbh nearby but not at the direct center of a galaxy would most likely:
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if the intensity of radiation 3.0 cm from a source is 300. mci, what is the intensity 1.0 cm from the source?
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A 9 V battery is connected in series with a resistor .The terminal voltage is found to be 8 V.Current through the circuit is measured as 5 A. What is the internal resistance of the battery?
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A string is wrapped several times around the rim of a hoop with radius R = 0.25 m and mass M = 0.75 kg. The free end of the string is attached to the ceiling and the hoop is released from rest. The moment of inertia of the hoop about its center is I = MR2 On the diagram above show all the forces applied on the hoop.Find the acceleration of the center of the hoop when it descends and the string unwinds.Find the tension force in the string.Calculate the time it takes the hoop to descend 1 m.Calculate the angular speed of the hoop after it has traveled 1 m.
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microwave radiation traveling in space has a frequency of 1.17306 1011 hz and a wavelength of 2.5556 mm. how fast does this radiation travel?
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a traveling electromagnetic wave in a vacuum has an rms electric field amplitude of 61.7 v/m. calculate the intensity s of this wave.
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A uniform beam of length x = 1.0 m and mass 10kg is attached to a wall by a cable at angle = 30 to the horizontal. The beam is free to pivot at the point where it attaches to the wall. What is the tension of the cable?
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1. Find the work done: a) work done = ? force = 40 N distance = 2.5m
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m3.13. diode, 5 in series treat all diodes with the offset-ideal model having a of volts. and . how much current flows through the resistor? 0.05500 a 0.110000 a 0.00000 a 0.0275000 a 5.50000 a
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The air in a house is at and 65 percent relative humidity. Now the air is cooled at constant pressure. The temperature at which the moisture in tThe air in a house is at and 65 percent relative humidity. Now the air is cooled at constant pressure. The temperature at which the moisture in the air will start condensing is(a) (b) (c) (d) (e)
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an ultrashort pulse has a duration of 7.80 fs and produces light at a wavelength of 476 nm . part a what is the momentum of a single photon in the pulse? express your answer to three significant figures and include the appropriate units.
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A laser beam shines along the surface of a block of transparent material. Half of the beam goes straight to a detector, while the other half travels through the block (2.50 m long) and then hits the detector. The time delay between the arrival of the two light beams at the detector is 6.25 ns. What is the index of refraction of the material?
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As you can see, a metal weight is placed in a plastic cylindrical tub floating in a tank, causing the tub to partially sink. Which force(s) are causing the tub to sink? Hint: What object would such a force have to act on? Select all that apply: The force of earth's gravity acting on the weight The force of earth's gravity acting on the tub The buoyant force acting on the weight The buoyant force acting on the tub The normal force of the weight acting on the tub
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when illuminated by red light of frequency f = 6 x 1014 hz, what is the stopping voltage of a photocell, made of a metal plate with a work function w = 2 ev?
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