B. The velocity of the second flight is negative compared to the speed.
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.
Answer:

we can see that this time period is independent of the mass of the child so answer would be same if the child mass is different
Explanation:
Natural frequency of a simple pendulum of L length is given as

so the time period of the oscillation is given as

so we will have



also from above formula we can see that this time period is independent of the mass of the child so answer would be same if the child mass is different
Answer:
15 less mins will be used by Bob
Explanation:
This is because it takes Tim 2000/50= 40mins to type the whole work
While it takes Bob 2000/80= 25 mins
So the difference 40-25= 15mins
Will be 15mins