Question

Three objects 1, 2, and 3, are lifted at constant velocity from the same floor to heights listed in the table below. The weight of the objects are also in the table, along with the time that was required to lift the objects.
On which object was the most work done by the lifting force, and which object was lifted with the greatest power?

Object	Weight	Height	Time
1	5.0 N	2.0 m	2.0 s
2	10.0 N	3.0 m	10.0 s
3	7.0 N	5.0 m	35.0 s

• A. Work Done: Object 1 and Greatest Power: Object 3
• B. Work Done: Object 1 and Greatest Power: Object 2
• C. Work Done: Object 2 and Greatest Power: Object 3
• D. Work Done: Object 3 and Greatest Power: Object 1

Answer 1

The correct option is D Work Done: Object 3 and Greatest Power: Object 1

$\text{For object-1 work done is mgh = 5X10X2=100J and power is mgh/t=50W.}$

$\text{For object-2 work done is mgh = 10X10X3=300J and power is mgh/t=30W.}$

$\text{For object-3 work done is mgh = 7X10X5=350J and power is mgh/t=10W.}$