J.J. Thomson discovered the electron by noticing that a beam of particles could be influenced by an electric or magnetic force.. That is option B.
<h3>What is an electron?</h3>
An electron can be defined as the part of an atom that is negatively charged and is found revolving round the nucleus of an atom.
J.J. Thomson was the scientist that discovered electrons through subjecting two oppositely-charged electric plates around the cathode ray.
He noticed that the particles where deflected by both the magnetic and electric fields.
Learn more about cathode rays here:
brainly.com/question/4441361
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Answer:
0.20
Explanation:
The box is moving at constant velocity, which means that its acceleration is zero; so, the net force acting on the box is zero as well.
There are two forces acting in the horizontal direction:
- The pushing force: F = 99 N, forward
- The frictional force: 
, backward, with
coefficient of kinetic friction
m = 50 kg mass of the box
g = 9.8 m/s^2 gravitational acceleration
The net force must be zero, so we have
which we can solve to find the coefficient of kinetic friction:
Answer:
The density of a material affects the speed that a wave will be transmitted through it. In general, the denser the transparent material, the more slowly light travels through it.
