In a hydroelectric power plant, 65 m3/s of water flows from an elevation of 90 m to a turbine, where electric power is generated. The overall efficiency of the turbine–generator is 84 percent. Disregarding frictional losses in piping, estimate the electric power output of this plant.

PHYS-91; Multiple Choice: A 10,000-watt motor operates an elevator weighing 5000 newtons. Assuming no frictional losses, how high is the elevator raised in 10 seconds. Is it raised: w) 2 meters x) 20 meters y) 50 meters z) 100 meters PHYS-91; Multiple Choice: A machine's output is 4000 joules and its frictional losses are 1000 joules. Which of the following is its efficiency? Is it: w) 25% x) 30% y) 75% z) 80% PHYS-91; Multiple Choice: A machine having an efficiency of 50% does 500 joules of work. Which of the following is the work input? Is it: w) 500 joules x) 250 joules y) 1000 joules z) 2500 joules

(II) (a) How much energy is transformed by a typical 65-kg person who runs at for in one week (Table 15–2)? (b) How many food calories would the person have to eat to make up for this energy loss?

#1) in 2021, the tallest building in the world, the Burg khalifa, klas estimated at $1.5 billion. Suppose used to pay for an ordinary used. by 0.35 KW micro klave oven at a rate of $0.56/kw-h. this money the energy KS (e) How much energy with this $1.5 billon? to (in kJ) can be supplied (b) How long (in years) can the microwave oven be powered? please show step by step workings.

(1)An energy-efficient lightbulb, taking in 23.0 W of power, can produce the same level of brightness as a conventional lightbulb operating at power 100 W. The lifetime of the energy-efficient bulb is 10 000 h and its purchase price is $4.00, whereas the conventional bulb has lifetime 750 h and costs $0.46 per bulb. Determine the total savings obtained by using one energy-efficient bulb over its lifetime as opposed to using conventional bulbs over the same time period. Assume an energy cost of $0.20 per kilowatt-hour.$

A crate of mass 9.8 kg is pulled up a rough indine with an initial speed of 1.54 mys. The pulling force is 9N parallel to the incline, which makes an angle of 20.1 with the hortaontal. The coefficient of kinetic friction is 0.400, and the crate is puled .02 m. (a) How much work is done by the gravitational force on the crate? (b) Determine the increase in internal energy of the crate-indine system owing to frietion. (e) How much work is done by the 98-N force on the crate? (4) what is the change in kinetic energy of the crate? (w) what is the speed of the crate after being puled 5.02 m m/s

O A 70 kg hiker climbed a mountain 1000 m high. He reached the peak in 3 hr. (a) Calculate the external work done by the climber. (b) Assuming the work was done at a steady rate during the 3 hr period, calculate the power generated during the climb. (c) Assuming the average O, consumption during the climb was 2 liters/min (corresponding to 9.6 kcal/min), find the efficiency 'of the hiker's body. (d) How much energy appeared as heat in the body?

At typical nuclear power plants, refueling occurs every 17 months. Assuming that a plant has operated continuously since the last refueling and produces 1.6 GW of electrical power at an efficiency of 25%, how much less massive are the fuel rods at the end of the 17 months than at the start? (Assume 30-day months.)

(i) Electrical Energy(in kWh) consumed by four Air conditioners of rating 2400 W for 12 h of each day= Answer for part 1 (ii) Electrical Energy(in kWh) consumed by two Electric Freezers of rating 1250 W for 24 h of each day= Answer for part 2 (iii) Electrical Energy(in kWh) consumed by ten Tube lights of rating 30 W for 12 h of each day = Answer for part 3 (iv) Total energy(in kWh) consumed in the month November'2020 = Answer for part 4 (v) Electricity bill(in riyals) for the month of November'2020 = Answer for part 5