How much work does a bricklayer do to carry 30.2 kg of bricks from the ground up to the third floor (height = 11.1 m) of a building under construction? What is the gravitational potential energy of the brick-Earth system when the bricklayer reaches the third floor?

Work done by the bricklayer, W = 3.285 kJ

Therefore, the gravitational potential energy of the brick-Earth system =  3.285 kJ

Explanation:

Work done is the product of applied force and distance moved by the force.

The force on an object in the gravitational field is equal to the product of the mass of the object and acceleration due to gravity This force is the weight of the object or body. In lifting an object from a lower height to a higher one, the distance moved is equal to the increase in height.

Work done in lifting an object in a gravitational field = mgh

where m = mass of the object, g = acceleration due to gravity, h = height

From the question, m = 30.2 kg, g = 9.8 m/s², h = 11.1 m

Work done by the bricklayer = 30.2 * 9.8 * 11.1 = 3285.156 J

Work done by the bricklayer, W = 3.285 kJ

Gravitational Potential Energy, PEg = mgh = W

Therefore, the gravitational potential energy of the brick-Earth system =  3.285 kJ

-4 on

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg