A construction hoist does 2.74x10⁴J of work in lifting a load of bricks from the street to the roof of a building. The roof is 9.46m above the street. Calculate the mass of a load of bricks. The load is moving at a constant rate
m * 9.81 * 9.46 = work done
Mass or Weight?
work=weight*height
weight=2.74e4/9.46 Newtons.
To solve this problem, we can use the concept of work and the gravitational potential energy formula.
The work done by the construction hoist is given as 2.74x10⁴J. This represents the energy transferred to the bricks to lift them from the street to the roof of the building.
The gravitational potential energy (PE) of an object is given by the formula:
PE = mgh
Where:
PE is the gravitational potential energy
m is the mass of the object
g is the acceleration due to gravity (approximately 9.8 m/s²)
h is the height or vertical distance travelled
In this case, the gravitational potential energy is equal to the work done by the construction hoist. So, we can set up the equation:
2.74x10⁴J = mgh
We are given that the height (h) is 9.46m. Plugging in the values, we get:
2.74x10⁴J = mg × 9.46m
To find the mass of the load of bricks (m), we need to rearrange the equation:
m = (2.74x10⁴J) / (9.46m × 9.8 m/s²)
Now, let's calculate:
m = (2.74x10⁴J) / (9.46m × 9.8 m/s²)
m ≈ 294.9 kg
Therefore, the mass of the load of bricks is approximately 294.9 kg.
As for the statement that the load is moving at a constant rate, this information does not affect our calculation for finding the mass of the load. It only states that the velocity of the load remains constant during the lifting process.