Concept: Power: The rate of doing work or energy is known as power (P). P = \(\frac{W}{T}\) Where, W = work in Jule. T = time in seconds. E = energy in Jule. • A unit of power is a watt. or Joule/second. • The dimensional formula of Power is [M^(1)L^(2)T^(-3)] • Another unit of power is horsepower 1 hp = 746 Watt. Work: work is defined as the product of force and displacement in the direction of the force. W = Ḟ⋅ s Where, F = Applied force. s = displacement in the direction of the force. Kinetic Energy: Energy formed due to the motion of the object If the body has mass (m) moving with velocity (v) Then, K.E = \( \frac{1}{2}\)mv^(2). Potential Energy: A body having mass (m) at height (h) from the ground and acceleration due to gravity (g) Then, P.E = mgh. Calculation: Given, Mass of bag = 25 kg Height = 5 m. Time = 30 sec \( power = \frac{{W}}{{T}}or\frac{{E}}{{T}}\) Power = \( power = \frac{{mgh}}{{time}} = \frac{{25 \times 9.8 \times 5}}{{30}} = 40.833 W\) The power needed by a man to carry a bag is 40.833 W.