Consider, please, this solution:
The final heat is:
Q=Q₁+Q₂+Q₃≈726.116 kJ
All the details are in the attachment.
Answer:
Oracio is the most cost-effective choice because he would cost the least to complete the project. However, he would also take the longest amount of time. Camilla could complete the job the fastest, but she costs more than Oracio. SciTech will have to decide if it is more important to save money or complete the work quickly to meet the deadline.
Hope this helps :)
The distance covered by an object accelerating from rest is
D = (1/2) · (acceleration) · (time)² .
In this particular case, 'acceleration' is 9.8 m/s² ... due to gravity.
D = (1/2) · (9.8 m/s²) · (1.67 s)²
D = (4.9 m/s²) · (2.789 s²)
D = 13.67 meters