Question

A machine has a MA of 6.0. The work input needed by the machine to raise a 40-kg load by 3.0 m is:

a) 0.12 kJ
b) 0.20 kJ
c) 1.2 kJ
d) 7.1 kJ

Answer 1

To find the work input required by a machine with a mechanical advantage of 6.0 to lift a 40-kg load 3.0 m, calculate the work output (weight lifted times height) and then divide by the machine's MA. Convert the result to kilojoules.

Step-by-step explanation:

The subject question involves calculating the work input needed by a machine to raise a load. Given the machine's Mechanical Advantage (MA) of 6.0, we can find the work output first and then the work input using the relationship between MA and work. The work output, in this case, is the gravitational work done on the 40-kg load to lift it 3.0 m, which can be calculated using the formula Work = Force x Distance. In this scenario, the force is the weight of the load, which is the product of the mass and the acceleration due to gravity (g = 9.8 m/s2). After calculating the work output, we divide it by the MA to find the work input. Since 1 kJ = 1000 J, we can convert our final answer into kilojoules to match the answer choices.