5470: Work & Power

Front

What is Work in physics?

Back

Work is defined as the product of the force applied to an object and the distance over which that force is applied, in the direction of the force. It is calculated using the formula: Work (W) = Force (F) × Distance (d) × cos(θ), where θ is the angle between the force and the direction of motion.

Front

What is Power in physics?

Back

Power is the rate at which work is done or energy is transferred over time. It is calculated using the formula: Power (P) = Work (W) / Time (t). The unit of power is the Watt (W), where 1 Watt = 1 Joule/second.

Front

What is the relationship between Work and Energy?

Back

Work is a transfer of energy. When work is done on an object, energy is transferred to that object, resulting in a change in its kinetic or potential energy.

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What does a negative value of work indicate?

Back

A negative value of work indicates that the force applied is in the opposite direction to the displacement of the object. This typically means that energy is being taken away from the object.

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How can power output be increased?

Back

Power output can be increased by decreasing the amount of time in which work is done, or by increasing the amount of work done in a given time.

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What is the formula for calculating work done against friction?

Back

The work done against friction can be calculated using the formula: Work (W) = Friction Force (Ff) × Distance (d). This work is often negative as it opposes the motion.

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What is the significance of the angle in the work formula?

Back

The angle (θ) in the work formula determines how much of the applied force contributes to the work done. If θ = 0°, all the force contributes to work; if θ = 90°, no work is done.

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What is Kinetic Energy?

Back

Kinetic Energy (KE) is the energy of an object due to its motion, calculated using the formula: KE = 1/2 mv², where m is mass and v is velocity.

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What is Potential Energy?

Back

Potential Energy (PE) is the energy stored in an object due to its position or configuration, commonly calculated using the formula: PE = mgh, where m is mass, g is the acceleration due to gravity, and h is height.

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What is the work-energy principle?

Back

The work-energy principle states that the work done on an object is equal to the change in its kinetic energy. This principle can be expressed as: W = ΔKE.