Podcast
Questions and Answers
What is the work done when a force of 50 N moves an object 4 m without an angle involved?
What is the work done when a force of 50 N moves an object 4 m without an angle involved?
Which of the following is the correct formula for calculating power?
Which of the following is the correct formula for calculating power?
How much kinetic energy does a 500 kg car moving at 10 m/s possess?
How much kinetic energy does a 500 kg car moving at 10 m/s possess?
What is the potential energy of a 3 kg object held 15 meters above the ground?
What is the potential energy of a 3 kg object held 15 meters above the ground?
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What power is developed by a force of 400 N moving an object at a velocity of 2 m/s?
What power is developed by a force of 400 N moving an object at a velocity of 2 m/s?
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What is the work done in lifting a 15 kg box 2 meters vertically?
What is the work done in lifting a 15 kg box 2 meters vertically?
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What is the angle in degrees that would result in zero work done while pushing an object?
What is the angle in degrees that would result in zero work done while pushing an object?
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A sled pulled with a force of 25 N at an angle of 60° over a distance of 8 meters performs how much work?
A sled pulled with a force of 25 N at an angle of 60° over a distance of 8 meters performs how much work?
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Study Notes
Work
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Formula: Work (W) = Force (F) × Distance (d) × cos(Φ)
- W: Joules (J)
- F: Newtons (N)
- d: meters (m)
- Φ: Angle between force and direction of motion
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Examples:
- Lifting a 10 kg box 2 meters: 196 J
- Pushing a cart with 50 N force over 5 meters: 250 J
- Pulling a sled with 30 N at 30° over 10 meters: 259.8 J
Power
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Mechanical Power Formula: Power (P) = Work (W) / Time (t)
- P: Watts (W)
- W: Joules (J)
- t: Seconds (s)
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Examples:
- Lifting weights with 500 J of work in 10 seconds: 50 W
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Force and Velocity Formula: Power (P) = Force (F) × Velocity (v)
- P: Watts (W)
- F: Newtons (N)
- v: meters per second (m/s)
- Example: A force of 100 N moves an object at 5 m/s: 500 W
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Force and Distance Over Time Formula: Power (P) = Force (F) × Distance (d) / Time (t)
- P: Watts (W)
- F: Newtons (N)
- d: meters (m)
- t: seconds (s)
- Example: A force of 200 N moves an object 10 meters in 5 seconds: 400 W
Kinetic Energy
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Formula: Kinetic Energy (KE) = ½ × mass (m) × velocity² (v²)
- KE: Joules (J)
- m: kilograms (kg)
- v: meters per second (m/s)
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Examples:
- 1000 kg car at 20 m/s: 200,000 J
- 70 kg person at 5 m/s: 875 J
- 2 kg object at 10 m/s: 100 J
Potential Energy
- Formula: Potential Energy (PE) = mass (m) × acceleration due to gravity (g) × height (h)
- PE: Joules (J)
- m: kilograms (kg)
- g: 9.8 m/s²
- h: meters (m)
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Examples:
- 5 kg object at 10 meters: 490 J
- 1000 kg water at 5 meters: 49,000 J
- 2 kg pendulum bob at 2 meters: 39.2 J
Elastic Potential Energy
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Formula: Elastic Potential Energy (EPE) = ½ × spring constant (k) × displacement² (x²)
- EPE: Joules (J)
- k: Newtons per meter (N/m)
- x: meters (m)
-
Examples:
- Spring with k = 200 N/m compressed by 0.5 meters: 25 J
- Rubber band with k = 30 N/m stretched by 0.2 meters: 0.6 J
- Bungee cord with k = 50 N/m stretched by 1 meter: 25 J
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Description
This quiz covers key formulas and concepts related to work and power in physics. It includes examples illustrating the calculations of work done and power generated through various scenarios involving force, distance, and time. Test your understanding of these fundamental concepts in mechanics.
