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Questions in physics

[Free] What is the major cause of tides? A. Earth's rotation B. the gravitational pull of the Moon on the Earth's water C. Earth's movement around the Sun D. the tidal bulge

[Free] 2. Nowadays Mr. Mumin is producing one kind of gas from the excrement of animal farms. He can sell extra gas after fulfilling the demand of his own firm. a) What is power? b) Describe the necessity of energy transformation. c) Explain the nature of the source of energy of the gas produced by stimulator. d) Analyze the importance of activities of Mr. Mumin regarding energy conservation.

[Free] Which of the following does not affect the electrical resistance of a body? A. Length of the body B. Material composing the body C. Temperature of the body D. Bodies directly surrounding the body

[Free] An object starts with a speed of u m/s and travels along a straight line. Speed increases at the rate of a m/s every second. The distance travelled in time t seconds is ut + 1/2 at^2. The distance travelled in 2 seconds is 10 metres and the distance travelled in 4 seconds is 28 metres. What was the initial speed? What is the rate at which speed is increasing?

[Free] 3 a. In a wood fire, 70% of the chemical energy in wood is changed to thermal energy. The remaining energy is changed to light and waste chemicals. Calculate the percentage of the chemical energy in the wood that is changed to light and waste chemicals. b. In an oil-burning power station, 55% of the chemical energy in the oil is changed to thermal energy and 10% is used in the power station. The remainder is changed to electrical energy. Calculate the percentage of the chemical energy in the oil that is changed to electrical energy. 4. Sofia has an LED flashlight that uses 18 J of electrical energy. 7 J of the electrical energy is wasted as thermal energy. Sofia says that 12 J of the electrical energy is changed to light. Explain whether Sofia is correct.

[Free] Select the correct answer from the drop-down menu. A scientist digs up a sample of arctic ice that is 458,000 years old. He takes it to his lab and finds that it contains 1.675 grams of krypton-81. If the half-life of krypton-81 is 229,000 years, how much krypton 81 was present when the ice first formed? Use the formula [tex]$N=N_0\left(\frac{1}{2}\right)^{\frac{t}{T}}$[/tex]. The ice originally contained $\square$ grams of krypton 81.

[Free] Xhangest law provide a method us alculate ary alection Thend Mish sh application in fields of inghly symmetric sistributesem ar in wat changess 8. In dianing electric ficid lines for any static configuration of charmes. shac inch and terminare on charges $A,+\cdots+13,+4,+1) \ldots$ 9. The electric field is defined as the force post unif change exerast on a samiliss $\frac{ kg _2 g_2}{r^3}$ D. $F=\frac{4 \times 92}{4 \pi a^2}$ 10. The lmaginary surface necessary to apply Cuuss law is called Bipolar Surface Q. Ciaussian Surface 1. None of the above 1. If the surface under consideration is not perpendicular to the fista line, une given as $A, \Sigma B A \cos 0$ 3. $2 E A \cos \pi C \quad 2 E \cos \theta \quad D \quad 2 . A \cos \theta$ 7. What is the integral form of the cxpression 2 , EA cos $0=\frac{0}{0}$ : A. 5 $P f E \cdot A=\frac{Q}{\varepsilon_s}$ $C \cdot \int A \cdot d E=\frac{1}{B a}$ 1). $\int E / A=\frac{0}{4 a}$

[Free] Which equation can be used to solve for acceleration? [tex]t=\frac{\Delta v}{a}[/tex] [tex]v f=a t-v[/tex] [tex]a=\frac{d}{t}[/tex] [tex]\Delta v=\frac{a}{t}[/tex]

[Free] 1. What did you observe about how particle motion changes from solid to gas? 2. Why do you think gases take the shape and volume of their container? 3. How does temperature affect the motion of particles in each state?

[Free] Light changes its direction when going from one medium to another transparent medium. This is the _________ of light. (A) Reflection (B) Dispersion (C) Refraction (D) Absorption