Question

3 Physics questions



1. A steam shovel raises 450.0 kg of dirt a vertical distance of 8.6 m. The engine provides 200KJ of energy as heat for the steam shovel to lift the dirt. How much work, in Joules, is done by the steam shovel? Use g as 9.81m/s2.WRITE YOUR ANSWER IN SCIENTIFIC NOTATION


2. A coal-burning power plant has an efficiency of 35 percent. If the power plant uses 737M J of energy as heat, how much work is done by the power plant?


3. A certain diesel engine performs 372 J of work in each cycle with an efficiency of 33.0 percent. How much energy is transferred from the engine to the exhaust and cooling system as heat?

Answer 1

Based on the work done of machines:

• Work done by steam shovel = 3.796 × 10^5 Joules
• Work done by power plant = 257.95 MJ
• Work lost as heat = 755.27 J

What is the work done by the steam shovel?

Work done is calculated using the formula:

• Work done = Force × distance
• Force = mass × acceleration due to gravity

work done = 450 × 9.81 × 8.6

Work done by steam shovel = 3.796 × 10^5 Joules

What is work done by the power plant?

The efficiency of a machine is calculated using the formula:

• Efficiency = work done by machine/work done on machine × 100%

Therefore:

• Work done by machine = efficiency × work done on machine/100

Work done by machine = 35 × 737/100

Work done by power plant = 257.95 MJ

What is the work done transferred from the engine and exhaust cooling system as heat.

The efficiency of a machine is calculated using the formula:

• Efficiency = work done by machine/work done on machine × 100%

Therefore:

• Work done on the machine = work done by the machine × 100/ efficiency

Work done on the machine = 372 × 100/33

Work done on the machine = 1127.27

Then, the work lost as heat is calculated using the formula:

Work lost as heat = work done on machine - work done by machine

Work lost as heat = 1127.27 - 372

Work lost as heat = 755.27 J

Therefore, based on the work done of machines:

• Work done by steam shovel = 3.796 × 10^5 Joules
• Work done by power plant = 257.95 MJ
• Work lost as heat = 755.27 J

Learn more about work done at: https://brainly.com/question/8119756