Power and Work

Understanding the concepts of Power and Work is essential for ICSE Physics. These concepts are foundational in mechanics and help us analyze how energy is transferred or transformed in various situations.

What is Work?

In physics, work is done when a force is applied to an object, causing it to move in the direction of the force. The amount of work done depends on the force applied and the distance over which it acts.

Work (W) = Force (F) × Displacement (d) × cos(θ)
Where:

• W = Work done (in Joules)
• F = Force applied (in Newtons)
• d = Displacement (in meters)
• θ = Angle between force and displacement

What is Power?

Power is the rate at which work is done or energy is transferred. It tells us how quickly work is being performed.

Power (P) = Work Done (W) / Time (t)
Where:

• P = Power (in Watts)
• W = Work done (in Joules)
• t = Time taken (in seconds)

Units of Work and Power

• Work: Joule (J)
• Power: Watt (W)

Examples

Example 1: Calculating Work

A box is pushed with a force of 50 N across a distance of 5 m. If the force is applied in the direction of motion, how much work is done?

Solution:

Work = Force × Displacement
W = 50 N × 5 m = 250 J

Example 2: Calculating Power

If the above work (250 J) is done in 10 seconds, what is the power developed?

Solution:

Power = Work / Time
P = 250 J / 10 s = 25 W

Key Takeaways

• Work is done when a force moves an object in the direction of the force.
• Power measures how quickly work is done.
• Units: Work (Joule), Power (Watt).

These concepts are crucial for understanding various phenomena in physics, and mastering them will help you in your ICSE exams.