Answer:
Power = 2.45Kw or 2450 Watts.
Explanation:
<u>Given the following data;</u>
Mass, m = 250kg
Height, h = 2m
Time, t = 2secs
We know that acceleration due to gravity, g is equal to 9.8m/s²
Power can be defined as the energy required to do work per unit time.
Mathematically, it is given by the formula;
But Energy = mgh
Substituting into the equation, we have

Power = 2450 Watts
To convert to kilowatt (Kw), we would divide by 1000
Power = 2450/1000
Power = 2.45Kw.
Therefore, the average power output of the weightlifter is 2.45 Kilowatts.
The movement of a fluid during convection is a circular/oval motion since the fluid at the top sinks and the fluid at the bottom rises.
Hope this helps :)
Answer:
(a) p = 3.4 kg-m/s (b) 37.78 N.
Explanation:
Mass of a basketball, m = 0.4 kg
Initial velocity of the ball, u = -5.7 m/s (as it comes down so it is negative)
It rebounds upward at a speed of 2.8 m/s (as it rebounds so positive)
(a) Change in momentum = final momentum - initial momentum
p = m(v-u)
p = 0.4 (2.8-(-5.7))
p = 3.4 kg-m/s
(b) Impulse = change in momentum
Ft = 3.4
We have, t = 0.09 s

Hence, this is the required solution.
The correct answer as the first one above !
The work done by the machine is equal to the product between the force applied and the distance over which the force is applieds, so in this case:

And the power of the machine is equal to the ratio between the work done by the machine and the time taken: