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Questions and Answers
What is the definition of work in physics?
What is the definition of work in physics?
- Work is defined as the product of force and distance in the direction of the force. (correct)
- Work is defined as the total energy of an object.
- Work is defined as the rate of energy transfer.
- Work is defined as the change in kinetic energy.
Which of the following units is NOT equivalent to work?
Which of the following units is NOT equivalent to work?
- Foot-pound
- Watt (correct)
- Joule
- Newton metre
If a force of 20N moves an object through 15m, how much work is done?
If a force of 20N moves an object through 15m, how much work is done?
- 300 J (correct)
- 400 J
- 50 J
- 150 J
What is the formula to calculate work done when a force is applied at an angle?
What is the formula to calculate work done when a force is applied at an angle?
How is the work done against gravity calculated when lifting a mass?
How is the work done against gravity calculated when lifting a mass?
A boy runs up a staircase with 30 steps, where each step is 15cm high. If his mass is 80kg and g = 10 m/s², how much work is done by the boy?
A boy runs up a staircase with 30 steps, where each step is 15cm high. If his mass is 80kg and g = 10 m/s², how much work is done by the boy?
When lifting a mass of 12kg through a distance of 1.25m with a force of 35N, what is the work done?
When lifting a mass of 12kg through a distance of 1.25m with a force of 35N, what is the work done?
What information is needed to calculate work when a force is applied at an angle?
What information is needed to calculate work when a force is applied at an angle?
What is the formula for calculating work done?
What is the formula for calculating work done?
Which type of energy is stored in the nucleus of atoms?
Which type of energy is stored in the nucleus of atoms?
What is the unit of measurement for energy?
What is the unit of measurement for energy?
How is potential energy calculated?
How is potential energy calculated?
If a body of mass 30 kg is lifted to a height of 5 m, what is its potential energy? (Use g = 10 m/s²)
If a body of mass 30 kg is lifted to a height of 5 m, what is its potential energy? (Use g = 10 m/s²)
What type of energy is characterized by a body in motion?
What type of energy is characterized by a body in motion?
What is the potential energy of an object with a mass of 0.55 kg at a height of 14.2 m? (Use g = 10 m/s²)
What is the potential energy of an object with a mass of 0.55 kg at a height of 14.2 m? (Use g = 10 m/s²)
If an object has a potential energy of 55 Joules and a mass of 15 kg, what is its height? (Use g = 10 m/s²)
If an object has a potential energy of 55 Joules and a mass of 15 kg, what is its height? (Use g = 10 m/s²)
Flashcards
Work
Work
Work is done when a force moves an object some distance in the direction of the force.
Work Formula
Work Formula
Work = Force x Distance
Work Unit
Work Unit
The SI unit of work is the joule (J).
Force Calculation
Force Calculation
Force = mass x acceleration (F=ma)
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Inclined Force Work
Inclined Force Work
Work done by a force at an angle = Fd cos θ
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Lifting Work Formula
Lifting Work Formula
Work = mgh (lifting)
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Work Calculation Example
Work Calculation Example
Calculating work done, for example, includes using the formula by plugging in the known values for force and distance.
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Calculating work against gravity
Calculating work against gravity
Work done against gravity is weight multiplied by the height.
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Potential Energy
Potential Energy
Potential energy is the stored energy an object has due to its position or state. It's the energy an object has the potential to use.
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Potential Energy Formula
Potential Energy Formula
Potential energy (PE) is calculated by multiplying the object's mass (m), acceleration due to gravity (g), and its height (h): PE = mgh
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Kinetic Energy
Kinetic Energy
Kinetic energy is the energy an object possesses due to its motion.
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Kinetic Energy Calculation
Kinetic Energy Calculation
Kinetic energy (KE) is calculated by multiplying 1/2 the object's mass (m) and the square of its velocity (v): KE = 1/2mv²
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Mechanical Energy
Mechanical Energy
Mechanical energy is the total energy of an object due to its motion and position. It's the sum of its potential energy and kinetic energy.
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Forms of Energy
Forms of Energy
Energy exists in different forms, including chemical, mechanical, nuclear, sound, hydro, and solar energy.
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Work, Energy & Power
- Work: Work is done when a force moves an object through a distance. For work to occur, the force must be applied in the direction of the displacement.
- Work Formula: Work = Force x Distance x cosθ, where θ is the angle between the force and the displacement
- Work is measured in Joules (J) or Newton-meters (Nm).
- Force is measured in Newtons (N).
- Distance is measured in meters (m).
- Force: Force = mass x acceleration (F = ma)
- Example Calculation: A force of 20N moves an object 15m. The work done is 300 Joules (20 N x 15 m = 300 J).
Different Forms of Energy
- Energy: Energy is the ability to do work. It is measured in Joules.
- Types of Energy:
- Chemical Energy
- Mechanical Energy (potential and kinetic)
- Nuclear Energy
- Sound Energy
- Hydro Energy
- Solar Energy
Potential Energy
- Potential Energy: Energy stored in an object due to its position or configuration.
- Gravitational Potential Energy (GPE):
- P.E. = mgh (mass x acceleration due to gravity x height)
- Example Calculation: An 80kg boy climbs 4.5m. GPE = 3600 J (80 kg x 10 m/s² x 4.5 m = 3600 J).
Kinetic Energy
- Kinetic Energy: Energy an object possesses due to its motion (movement).
- Kinetic Energy Formula: KE = 1/2mv² (one-half x mass x velocity²).
- Mass (m) is in kilograms (kg).
- Velocity (v) is in meters per second (m/s).
- Kinetic energy (KE) is in Joules (J).
- Example Calculation: A 25kg car moving at 15 m/s has kinetic energy of 2812.5 J (1/2 x 25 kg x (15 m/s)² = 2812.5 J).
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