The kinetic energy when it returns to its original height is 100 J
The ball is thrown up with a Kinetic Energy K. E. = 0.5×m×v² = 100 J
Therefore the final height is given by
u² = v² -2·g·s
Where:
u = final velocity = 0
v = initial velocity
s = final height
Therefore v² = 2·g·s = 19.62·s
P.E = Potential Energy = m·g·s
Since v² = 2·g·s
Substituting the value of v² in the kinetic energy formula, we obtain
K. E. = 0.5×m×2·g·s = m·g·s = P.E. = 100 J
When the ball returns to the original height, we have
v² = u² + 2·g·s
Since u = 0 = initial velocity in this case we have
v² = 2·g·s and the Kinetic energy = 0.5·m·v²
Since m and s are the same then 0.5·m·v² = 100 J.
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Answer:
0.5m
Explanation:
1m = 100cm 1×100 will give that answer so in converting 50cm into m you just need to do it vice versa ÷100 that will give you your answer which is 0.5m
Answer:
It should be option B polarization
Answer:
7.9 x 10^21 pound-force
Explanation:
The average distance between the Earth and sun is 150 trillion meters, or 1.5 x 10^11 meters. The mass of the sun is 1.99 x 10^30 kilograms, while the Earth weighs in at 6.0 x 10^24 kilograms. The gravitational constant is 6.67 x 10^-11 meter^3 / (kilogram - second^2). So the Earth and sun pull on each other with a force equal to 3.52 x 10^22 newtons. The newton is a unit of force equal to a kilogram-meter/second^2. One newton is equal to 0.22 of the rarely used English unit called pound-force, so 3.52 x 10^22 newtons is 7.9 x 10^21 pound-force.
Answer: A. 200J
Therefore, the workdone by the heat engine is 200J
Explanation:
Given ;
The efficiency of the heat engine is E = 20% = 0.2
Heat loss L= 800J
For an heat engine the efficiency is measured by the amount of workdone by the heat engine when compared to the heat generated.
Efficiency E = workdone/heat generated × 100%
Heat generated G= workdone W + heat loss L
G = W + L
According to the question.
W = 20% of G
W = 0.2G ......1
L = 80% of G
L = 0.8G
G = L/0.8 ......2
Substituting equation 2 to 1
W = 0.2(L/0.8)
And L = 800J
W = 0.2(800/0.8)
W = 200J
Therefore, the workdone by the heat engine is 200J
