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3 years ago

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A twig from a tree drops from a 200m high cliff on to a beach below.during its fall 40% twig's energy is converted into thermal

energy.what is the speed with which the twig hits the beach?

1 answer:

kolezko [41]3 years ago

7 0

<span>Calculating for potential energy P.E=mgh
m=mass
g=acceleration due to gravity
h=height
</span>Let the twig's mass be M<span>
</span><span>
therefore at the start, the twig has 200*9.8*M potential energy.

</span>During its fall 40% twig's energy is converted into thermal energy and the remaining <span>60% of this will turn into kinetic energy during the fall, giving us 1176M
Now the equation for kinetic energy, K.E is 0.5*m*v^2
m is mass
v is velocity

Therefore 1176M=0.5*M*v^2 (mass will divide out)
velocity is </span><span>48.49 m/s</span>

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Part b)

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Part c)

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electric field at r = 20 cm

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