Answer:
4.5 m/s
Explanation:
The rock must barely clear the shelf below, this means that the horizontal distance covered must be
while the vertical distance covered must be
The rock is thrown horizontally with velocity 
, so we can rewrite the horizontal distance as
where t is the time of flight. Re-arranging the equation,
(1)
The vertical distance covered instead is
where we omit the term 
since the initial vertical velocity is zero. From this equation,
(2)
Equating (1) and (2), we can solve the equation to find :
Newton's law of universal gravitation<span> states that a particle attracts every other particle in the universe with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers. hope this helps =)</span>
Answer:
In helium
Explanation:
Since the units are the same, the value should only be considered.
The efficiency of steam engine is 26.66 %.
<h3>What is Efficiency?</h3>
The efficiency is defined as the work done by the engine divided by the heat supplied.
Work done is the difference between the heat supplied and heat rejected.
So, efficiency η = (Qs -Qr) / Qs
Given is the heat supplied Qs = 225 Joules and heat rejected Qr =285 . then the work done is
W = 225 -225 = - 60 Joules
Efficiency η = 60/225 x 100%
η = 26.66 %
Thus, the efficiency of the steam engine is 26.66 %.
Learn more about efficiency.
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