00:01
So we are going to be looking at problem 8 of chapter 5 of the physics fifth book.
00:08
The question says, the man in the figure weighs 180 pounds, the platform and the attack friculous pulley wear a total of 43 pounds, ignoring the weight of the rope, with what force must the man pull up on the rope in order to lift himself and the platform upwards at 1 .2 feet per second square.
00:26
So let's first calculate our weight total, which is w of the platform plus w the man, and that comes up to be 223 pounds.
00:35
Now, in our system, we know we've got our platform, we've got our man pulling up some force, f man, and we've got some weight.
00:50
Actually, let me just make that a bit bigger.
00:52
We've got our man pulling up some weight, some force, f man, and we've got some weight going downwards.
01:03
So we have some total forward going upwards which results in the 1 .4 meters per second or sorry not feet per second squared...