When people are cutting trees down or cutting firewood they never wear any safety gear?I would think people would wear the following; helmet, chainsaw gloves, chainsaw pants, chaps and chainsaw shirts I currently use a Stihl 066, Stihl 361 Quickstop and a Jonsered 450. I know how to use a chainsaw. However, you see all types of people not wear protective clothing (Professional Homeowners.) What are some of the reasons?
The velocity required to reach 32 meter height is v^2 2 g h 2 (9.8 m/sec^2) (32 m) thus v 25.0 m/sec. The rate of flow of mass is therefore (25.0 m/sec) Pi (0.02 m)^2 (1000 kg/m^3) 31.4 kg/sec The power required is therefore (31.4 kg/sec) (32 m) (9.8 m/sec^2) 9847 (kg m^2/sec^2)/sec 9847 J/sec 9847 Watts Note that we could have calculated power differently. Force is change in momentum, so the force acting on the hose is: (31.4 kg/sec)(25 m/sec) 75 kg m/sec^2 785 Newtons Every second that force operates over a distance of 25 meters, so the power is (25 m/sec) (785 N) 19625 Nm/sec 19625 Watts Hmmmmm which is double the above result. Perhaps the asker or someone else can spot the error in one approach versus the other.
