Integrated Concepts A basketball player jumps straight up for a ball. To do this, he lowers his body 0.300 m and then accelerate
1 answer:
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Answer:
Some work input is lost to friction
Explanation:
The efficiency of a machine is defined as:
(1)
where
is the work output
is the work input
Due to the law of conservation of energy, the work output can never be larger than the work input (because energy cannot be created). Moreover, in real machines part of the work input is lost due to the presence of frictions: as a result, part of the energy in input is converted into thermal energy or other forms of energy, and so the work output is smaller than the work input, and so the ratio (1) becomes less than 1, and so the efficiency is less than 100%.
Answer:
Focal length of the lens is 8.2 cm.
Explanation:
It is given that,
Height of object, h = 4 cm
Object distance, u = -30 cm
Height of the image, h' = -1.5 cm (negative because the image is inverted)
We need to find the focal length of the lens. It can be calculated using lens formula as :
Magnification,
Image distance, v = 11.25 cm
f = 8.18 cm
or f = 8.2 cm
So, the focal length of the lens is 8.2 cm. Hence, this is the required solution.