B. kinetic energy increases and potential energy decreases
78.4 joules is the energy of a 4 kg apple that is sitting on a 2 m high tree branch.
<u>Explanation:
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When an apple falls to the ground from a tree, its positional energy (stored as potential gravitational energy) turns into kinetic energy, during a fall. Chemical potential energy is chemical energy because it is food and potential energy as it can still have ability to move. So, in the given case, kinetic energy is zero.
To find potential energy, the formula would be
Where, given
m – Mass – 4 kg
(Known value)
h – Height - 2 m
Substitute these values, we get
Answer:
look at the explanation
Explanation:
This pith-ball electroscope is used to detect the presence of a static electricity charge. The two lightweight “pith” balls suspended from the strings are attracted to objects with a static electric charge. The pith balls can also be charged by touching them to an object with a static electric charge.
Answer:
2.58 x 10⁸ m/s
Explanation:
Time dilation fomula will be applicable here, which is given below.
t = \frac{T}{\left ( 1-\frac{v^2}{c^2} \right )^\frac{1}{2}}
Where T is dilated time or time observed by clock in motion , t is stationary time , v is velocity of clock in motion and c is velocity of light .
c is 3 times 10⁸ ms⁻¹ , T is 7.24 h , t is 3.69 h. Put these values in the formula
7.24 = \frac{3.69}{\left ( 1-\frac{v^2}{c^2} \right )^\frac{1}{2}}\\
\frac{v^2}{c^2}=0.744\\\\
v=2.58\times 10^8
