Which statement correctly compares the speed of light
2 answers:
<u>Answer:</u> The correct answer is Option D.
<u>Explanation:</u>
Refractive index is defined as the ratio of speed of light in vacuum to the speed of light in medium. It is represented as . Speed of light in vacuum is always equal to
Mathematically,
If the refractive index is more, the speed of light in that medium will be slow and vice-versa.
As, the refractive index of glass is more than the refractive index of space. Hence, the speed of light will be slower in glass.
Therefore, the correct answer is Option D.
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Answer:
a). A conservative force permits a two-way conversion between kinetic and potential energies.
TRUE
Because there is no energy loss in presence of conservative forces so energy conversion in two ways are possible.
b). A potential energy function can be specified for a conservative force.
TRUE
negative gradient of potential energy is equal to conservative force
c). A non-conservative force permits a two-way conversion between kinetic and potential energies.
FALSE
here energy is lost against non-conservative forces
d). The work done by a conservative force depends on the path taken.
FALSE
work done by conservative force is independent of path
e). The work done by a non-conservative force depends on the path taken.
TRUE
work done by non conservative forces depends on path.
f). A potential energy function can be specified for a non-conservative force.
FALSE
It is not defined for non conservative forces
Answer:
The driver hits the stationery dog because the applied force is less than required force
Explanation:
Kinetic energy will be given by
where m is the mass of the vehicle and v is the speed/velocity of the vehicle.
Substituting 800 Kg for m and 20 m/s for v we obtain
Frictional force by vehicle pads is given by
where d is the distance moved
Substituting 160000 for KE and 50 m for d we obtain
Therefore, the vehicle hits the dog since the required force is 3200N but the driver applied only 2000 N