Test Session Chap#4: Work, Energy and Power (1st Year Physics)

Multiple Choice Questions (MCQs)

Short Answer Questions

Important Formulas

Work and Energy:

Work: W = F·d·cosθ

Kinetic energy: K = ½mv²

Potential energy: U = mgh

Total mechanical energy: E = K + U

Power:

Average power: P = W/t

Instantaneous power: P = F·v

Electrical energy: E = Pt

Conversions:

1 kWh = 3.6 × 10⁶ J

1 hp = 746 W

1 J = 1 N·m = 1 kg·m²/s²

Energy Calculator

Calculate Potential Energy:

Mass (kg):

Height (m):

Calculate Kinetic Energy:

Mass (kg):

Velocity (m/s):

Detailed Answer Questions

Question 1 (5 marks)

State and explain work-energy theorem in a resistive medium.

Question 2 (5 marks)

A 1200 kg car is running at a speed of 40 km h⁻¹. How much power will be expended by it to accelerate at 2 ms⁻². (Numerical Problem)

Question 3 (5 marks)

Define Absolute potential energy. Derive relation for absolute potential energy of body of mass ‘m’ at distance ‘r’ from the centre of earth.

Note: Answer any 2 questions. Each question carries 5 marks.

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