26. a 40 kg boy jumps from a height of 4m onto a plate-form mounted on springs. as the
spring compress, the plate-form is pushed down a maximum distance of 0.2 cm below its
initial position, and it then rebounds. what is the loss in potential energy by the boy?
a. 800j
b. 1080j
c. 1600j
d. 1680 j

c. 1600J

Explanation:

The loss in potential energy of the boy is given by:

where

m = 40 kg is the mass of the boy

g = 9.8 m/s^2 is the acceleration of gravity

is the total change in the height of the boy (4 metres + 2 cm due to the compression of the spring)

Substituting, we find

answer: the rock sample is a sedimentary rock.

explanation:

it is given that:

mass of rock sample, m = 2.7 g

volume of rock sample,

so, density of rock sample will be

since, the density of rock sample is . hence, the rock sample is a sedimentary rock, whose densities varies between .

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