The angle of incidence of a light beam in air onto a reflecting surface is continuously variable. The reflected ray is found to
1 answer:
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Answer:
ΔT = 302 °c
Explanation:
mass (m) = 4.6 g = 0.0046 kg
velocity (v) = 278 m/s
specific heat of lead (c) = 128 J/kg. °c
kinetic energy = 0.5 mx
kinetic energy = 0.5 x 0.0046 x
kinetic energy = 177.8 J
since all the kinetic energy is converted to thermal energy,
kinetic energy = thermal energy (E) = 177.8 J
thermal energy = m x c x ΔT
where ΔT is the temperature change
177.8 = 0.0046 x 128 x ΔT
ΔT = 177.8 / 0.59
ΔT = 302 °c
Answer:
-0.9045 j
Explanation:
Here K= 270 N/m
distance 1 = 4.60 mm=0.0046 m
when pen is compressed ;
distance 2 = 6.70 mm + distance1 = 0.0067 m+0.0046 m= 0.0113 m
The pen store in itself two types of PE
Which is Initial PEi = 1/2 ×K× [ =0.5×270×0.0046 =0.621 j
and Final PEf = 1/2 × K × = 0.5×270×0.0113=1.5255 j
When the pen gets ready - it goes ahead distance d2 and is then pressed back distance d1 for writing.
Total PE when ready = 0.621-1.5255= - 0.9045 j
so, work = -0.9045 j