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Questions in physics

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

📝 Answered - How far does a car travel in 90 seconds if it is traveling at a speed of 55 m/s? Show the appropriate equation from your textbook and show your work with units. (Chapter 2 – Pages 46-47)

📝 Answered - The gravitational force formula is [tex]F=\frac{G m m_2}{r^2}[/tex], where [tex]F[/tex] is the force between two objects, [tex]G[/tex] is the constant gravitation, [tex]m_1[/tex] is the mass of the first object, [tex]m_2[/tex] is the mass of the second object, and [tex]r[/tex] is the distance between the objects. By rewriting the formula as [tex]r=\sqrt{\frac{G m m_2}{F}}[/tex], you can find the distance between objects. Which of the following gives the distance, [tex]r[/tex], in simplest form? A. [tex]r=\frac{\sqrt{ Gm _2 m_2}}{F}[/tex] B. [tex]r=\frac{\sqrt{G m m_2 F}}{F}[/tex] C. [tex]r=\sqrt{G m_1 m_2 F}[/tex]

📝 Answered - For an object thrown at 45° to horizontal, the maximum height (H) and horizontal range (R) are related as: (1) R = 16H (2) R = 8H (3) R = 4H (4) R = 2H 19. A missile is fired for maximum range with an initial velocity of 20 m/s. If g = 10 m/s², the range of the missile is: (1) 40 m (2) 20 m (3) 60 m (4) 50 m 20. Velocity of a projectile in its flight: (1) Remains constant (2) First decreases, becomes zero and then increases. (3) First decreases, reaches minimum and then increases. (4) First increases, reaches maximum and then decreases. 21. At the maximum height of a projectile, the velocity and acceleration are: (1) Parallel to each other (2) Antiparallel to each other (3) Perpendicular to each other (4) Inclined to each other at 45°

📝 Answered - The Schrödinger wave equation for the hydrogen atom is: \[\psi_{2s} = \frac{1}{4\sqrt{2\pi}} \left( \frac{1}{a_0} \right)^{3/2} \left( 2 - \frac{r_0}{a_0} \right) e^{-\frac{r_0}{2a_0}} \], where \(a_0\) is Bohr's radius. If the value of \(a_0\) is 53 pm, then what is the value of the distance of the radial node (\(r_0\) in pm) from the nucleus?

📝 Answered - A cardboard box weighs 0.045 kg. What will be the weight of 9 such boxes?

📝 Answered - Match the following: (a) Gravitational force (b) Friction (c) Sound energy (d) Electrical energy (e) Muscular force (f) Magnetic force (g) Electrostatic force i. A comb attracting paper pieces ii. Pushing a box iii. Force between two moving objects that slows them iv. Students shouting at a playground v. An electric oven is an example of this vi. Water falling down from a tap is due to this vii. A magnet attracting metal coins

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

📝 Answered - State three ways of conserving energy in the home. An electrical appliance in the home uses 4000 W of electric power every 12 hours. Calculate the energy used within this time.

📝 Answered - A metal sphere A of radius a is charged to a potential V. It is enclosed inside a hollow metal shell B of radius b. What will be the potential of A if it is connected to shell B by a conducting wire? Show the working.