Protons, neutrons, and electrons<span> are the three main subatomic particles found in an atom. Protons have a</span>positive<span> (+) </span>charge<span>. An easy way to remember this is to remember that both proton and </span>positive<span> start with the</span>letter<span> "</span>P<span>." Neutrons have no electrical </span>charge<span>.</span>
Number 20 is B and 21 is C
Answer:
its most definitely c. trust me
Explanation:
Operant conditioning, sometimes called <em>instrumental learning</em>, was first extensively studied by Edward L. Thorndike, who observed the behavior of cats trying to escape from home-made puzzle boxes.
Hope this helps!
Answer:
The distance is
=
7
m
Explanation:
Apply the equation of motion
s
(
t
)
=
u
t
+
1
2
a
t
2
The initial velocity is
u
=
0
m
s
−
1
The acceleration is
a
=
2
m
s
−
2
Therefore, when
t
=
3
s
, we get
s
(
3
)
=
0
+
1
2
⋅
2
⋅
3
2
=
9
m
and when
t
=
4
s
s
(
4
)
=
0
+
1
2
⋅
2
⋅
4
2
=
16
m
Therefore,
The distance travelled in the fourth second is
d
=
s
(
4
)
−
s
(
3
)
=
16
−
9
=
7
m
