The scientist who discovered the laws of motion was _____.
1 answer:
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Answer:
B. use light of a shorter wavelength.
Explanation:
We know that
h= plank's constant
c= speed of light
λ= wavelength of the incident light
so, in order to have sufficient energy for for the emission of electron, the incident's radiation must have λ small enough.
B. use light of a shorter wavelength.
Question: How fast was the arrow moving before it joined the block?
Answer:
The arrow was moving at 15.9 m/s.
Explanation:
The law of conservation of energy says that the kinetic energy of the arrow must be converted into the potential energy of the block and arrow after it they join:
where is the mass of the arrow,
is the mass of the block,
of the change in height of the block after the collision, and
is the velocity of the arrow before it hit the block.
Solving for the velocity , we get:
and we put in the numerical values
,
and simplify to get:
The arrow was moving at 15.9 m/s