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Questions in physics

[Done] 9. A block with a mass of 2.0 kg is pulled across a horizontal plane by a horizontal force of 10 N. This force is just sufficient to overcome friction. Calculate the coefficient of friction between the block and the plane. 10. A block with mass (m) of 70 kg is pulled across a horizontal plane with a force (F) of 300 N. This force is just sufficient to overcome friction. Calculate the coefficient of friction between the block and the plane. 11. A block with a mass of 15 kg is pulled across a horizontal plane with a force of 44 N. Calculate the: (a) weight of the block (w). (b) coefficient of friction (μ) between the block and the horizontal plane. (c) pulling force required to pull a similar block of 2 kg mass under the same conditions. A force of 150 N is required to move a casting with a mass of 43 kg across a horizontal plane. Calculate the value of the coefficient of friction and the magnitude of the angle of rest. The coefficient of friction between a block and a horizontal plane is 0. Calculate the angle of rest.

[Done] An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?

[Done] An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?

[Done] An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?

[Done] An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?

[Done] What is the conclusion of the following argument? Not only is the sky blue (as a result of scattering), but light coming from it is also partially polarized. You can readily observe this by placing a piece of Polaroid (for example, one lens of a pair of Polaroid sunglasses) in front of your eye and rotating it as you look at the sky on a clear day. You will notice a change in light intensity with the orientation of the Polaroid.

[Done] Select the correct answer. The isotope calcium-41 decays into potassium-41, with a half-life of [tex]$1.03 \times 10^5$[/tex] years. There is a sample of calcium-41 containing [tex]$5 \times 10^9$[/tex] atoms. How many atoms of calcium-41 and potassium-41 will there be after [tex]$4.12 \times 10^5$[/tex] years? A. [tex]$3.125 \times 10^8$[/tex] atoms of calcium-41 and [tex]$4.375 \times 10^9$[/tex] atoms of potassium-41 B. [tex]$6.25 \times 10^6$[/tex] atoms of calcium-41 and [tex]$4.6875 \times 10^9$[/tex] atoms of potassium-41 C. [tex]$6.25 \times 10^8$[/tex] atoms of calcium-41 and [tex]$4.375 \times 10^9$[/tex] atoms of potassium-41 D. [tex]$3.125 \times 10^6$[/tex] atoms of calcium-41 and [tex]$4.6875 \times 10^9$[/tex] atoms of potassium-41

[Done] Which statement describes Newton's law of universal gravitation? A. Mass has little effect on gravity between objects. B. Gravity pushes objects away from Earth's center. C. Gravity does not act between Earth and the moon. D. Every object in the universe attracts every other object.

[Done] Assertion (A): In water, the value of the magnetic field decreases. Reason (R): Water is a diamagnetic substance.

[Done] What variable represents specific heat in the equation [tex]$Q=m c \Delta T$[/tex]? A. The variable [tex]$m$[/tex] B. The variable [tex]$Q$[/tex] C. The variable [tex]$c$[/tex] D. The variable [tex]$T$[/tex]