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Questions in physics

[Done] 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

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

[Done] 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.

[Done] 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.

[Done] Which feature is used to classify galaxies? A. age B. color C. shape

[Done] A body is a particular amount of matter. It can be a solid, liquid, or gas. It can be described as existing in A. location and movement. B. time and space. C. size and shape. D. motion and force.

[Done] True or False: How fast a car drives is an example of Newton's third law of motion.

[Done] Which statements best describe displacement? Check all that apply. A. Displacement is measured along the path an object travels. B. Displacement is a measurement that includes direction. C. Displacement is the difference between a starting point and an ending point. D. Displacement is how far an object travels from starting point to ending point. E. Displacement is measured as a straight line between a starting point and ending point.

[Done] (e) State two ways in which this household can reduce electrical energy consumption. 6. An air conditioner has a power rating of 3000 W and is used daily. Its electrical energy consumption is 120 kWh for one week. (a) Calculate, in hours, the average duration for which the air conditioner is used daily. (b) Given that the cost of electricity is $0.25 per kWh, calculate the total cost of using the air conditioner for one week.

[Done] A 100 W heater is connected to a 240 V mains supply. Calculate the: (i) current drawn; (ii) resistance of the heater.