The energy derived from digesting food is chemical energy . hope this helps :)
If the ladder is vertical, then the work done in ascending equals his increase in potential energy.
For a man of mass (m) climbing height (h), the PE is (mgh), where g is the acceleration due to gravity.
If he does this in time t, his average power (rate of working) is:
mgh / t
= 80 * 9.81 * 6 / 12
= 392.4 W.
If the ladder is not vertical but inclined at an angle the horizontal, the power is mgh sin(a) / t.
Answer:
advantage : 1) produce no polluting gases .
2)doesn't contribute to global warming .
disadvantage: 1)waste is radioactive and safe disposal is very difficult and expensive.
2)local thermal pollution from east water affects marine life
Answer:
120 km/hr
Explanation:
Let D be the distance between the rocket and the camera as the rocket is moving upwards. Let d be the distance the rocket moves and L be the distance between the camera and the base of the rocket = 4 km.
Now, at any instant, D² = d² + L²
= d² + 4²
= d² + 16 since the three distances form a right-angled triangle with the distance between the rocket and the camera as the rocket is moving upwards as the hypotenuse side.
differentiating the expression to find the rate of change of D with respect to time, dD/dt ,we have
d(D²)/dt = d(d² + 16)/dt
2DdD/dt = 2d[d(d)/dt]
dD/dt = 2d[d(d)/dt] ÷ 2D
Now d(d)/dt = vertical speed of rocket = 200 km/hr
dD/dt = 200d/D [D = √(d² + 16)]
dD/dt = 200d/[√d² + 16]
Now substituting d = 3 km, the distance the rocket has risen into the equation, we have
dD/dt = 200(3)/[√(3² + 16)]
dD/dt = 600/[√(9 + 16)]
dD/dt = 600/√25
dD/dt = 600/5
dD/dt = 120 km/hr
So, the speed at which the distance from the camera to the rocket changing when the rocket has risen 3 km is 120 km/hr.
Not possible. The air is actually able to travel sound throughout itself without any difficulties. I believe, air actually brings sound closer to the people farther away ; It really helps to stretch sound.