ANYONE ANSWER THIS QUESTION PLEASE! It's about energy, work and power. Having a hard time trying to solve this?

1. A motor does 5,000 joules of work in 20 seconds. What is the power of the motor?

2. A machine does 1,500 joules in work in 30 seconds. What is the power of this machine?

3. A hairdryer uses 72,000 joules of energy in 60 seconds. What is the power of this hairdryer?

4. A toaster oven uses 67,500 joules of energy in 45 seconds to toast a piece of bread. What is the power of the oven?

5. A horse moves a sleigh 1.00 kilometer by applying a horizontal 2,000-newton force on its harness for 45 minutes. What is the power of horse? ( Hint: Convert time to seconds )

6. A wagon is pulled at a speed of 0.40 meters/sec by a horse exerting an 1,800-newton horizontal force. What is the power of this horse?

7. Suppose a force of 100 newtons is used to push an object a distance of 5 meters in 15 seconds. Find the work done and the power for this situation.

8. Emily’s vacuum cleaner has a power rating of 200 watts. If the vacuum cleaner does 360,000 joules of work, how long did Emily spend vacuuming?

9. Nicholas spends 20 minutes ironing shirts with his 1,800-watt iron. How many joules energy were used by the iron? (Hint: convert time to seconds).

10. It takes a clothes dryer 45 minutes to dry a load of towels. If the dryer uses 6,750,000 joules of energy to dry the towels, what is the power rating of the machine?

1 Answer

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  • 9 years ago
    Favorite Answer

    1. Power is just the energy rate. So that would be 5000J/20s = 250W

    2. Same. 1500J/30s = 50W

    3. Same. 1200W or 1.2KW

    4. 1500W or 1.5KW

    5. Energy = F*d = 2000N * 1000m = 2000KJ

    2000KJ/(45min*60) (convert to seconds) = 0.741KW or 741W

    6. Same

    7. Same

    8. 200W = 360000/t ; t= 1800s

    9. 1800W = E / 20 * 60 ; E = 2160000J or 2160KW

    10. Same

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