Answer: 6067.5 N
Explanation:
Work = Change in Energy. To start, all of the energy is kinetic energy, so find the total KE using: KE = 1/2(m)(v^2). Plug in 1980 kg for m and 15.5 m/s for v and get KE = 237847.5 J.
Now, plug this in for work: Work = Force * Distance; so, divide work by distance to get 6067.5 N.
Amount of work done is zero and so power = 0 watts.
<u>Explanation:</u>
Power is the rate at which work is done, or W divided by delta t. Since the barbell is not moving, the weightlifter is not doing work on the barbell.Therefore, if the work done is zero, then the power is also zero.It may seem unusual that the data given in question is versatile i.e. A weightlifter exerts an upward force on a 1000-N barbell and holds it at a height of 1 meter for 2 seconds. But, still the answer is zero watts , this was a tricky question although conceptual basis of question was good! Power is dependent on amount of work done which is further related to displacement and here the net displacement is zero ! Hence, amount of work done is zero and so power = 0 watts.
Thank you for posting your question here at brainly. I would say yes to the above question. <span>Work done is the force applied multiplied by the distance travelled. </span><span>Wd = F x d. </span><span>So if d increases, Wd increases also. I hope the answer will help you. </span>
I'm not sure about the rest but for question 2:
A theory is an attempt to come up with a big picture of all we know so far. It also drives future research as people do experiments to see if what the theory predicts actually happens. When experiments don’t support the theory, you have to change the theory and try again. That’s how science works. We come up with a “best guess” (theory), and then do research to test it’s accuracy. As we discover contradictions, we adjust the theory to take those into account, and then start testing the validity of the new theory.
