Answer:
(a)
, 
(b) When
, object is slowing down, when
object is speeding up.
Explanation:
(a) To get the velocity function, we need to take the derivative of the position function.

To get the acceleration function, we need to take the derivative of the velocity function.

(b) The object is slowing down when velocity is decreasing by time (decelerating) hence a < 0

On the other hand, object is speeding up when a > 0

Therefore, when
, object is slowing down, when
object is speeding up.









☯ <u>Using 1st equation of motion </u>











☯ <u>Now, Finding the force exerted </u>







☯ <u>Hence</u>, 

Answer:
A- A demonstration shows how something works, often including models
Explanation:
A demonstration allows, through experimentation, to show how nature works and in that way can include the explanation of scientific theories that explain the set of observed facts, that is, it serves as a demonstration of the underlying scientific principles.
Answer:
b) vary with the frequency of the light
Explanation:
The phone electric effect can be expressed as
K.E=(hv -W•)
Where K.E is the Kinectic energy
W• = work function of the metal
ν =frequency of the radiation
h = Planck's constat
Then, we can see that K.E is proportional linearly to "v" in the equation above.
Therefore, When light is directed on a metal surface, the kinetic energies of the photoelectrons vary with the frequency of the light