Hi Babylilith32,
Your Question:
An experiment was devised to investigate the effects on the temperature of a cup of coffee when cream is added at different time intervals. Hot and cold water were used instead of coffee and cream. First, a container of water heated to 80°C was allowed to sit for 15 minutes. Its temperature was measured at regular intervals. Next, similar temperature measurements were taken for 15 minutes on a new container of heated water, but this time some cold water was added after the 2-minute reading. Finally, the procedure was repeated except that for this last test, the cold water was added after the 12-minute reading. The resulting recorded temperatures were plotted on the graph shown here.
Answers:
1. If you have cool water then you have to add it to the hot water after a few minutes.
2. The independant variable is the cold water
3. The dependant variable is the temperature
4. The control is the hot water without the cold water.
5. The 2 min cold water drops way to much.
Scientific Method: Because, they use their method which the scientific one to solve investigations.
It's always a good idea to start with the definition of the thing you're trying to find.
This problem is just trying to find out whether you KNOW the definition of acceleration. You may know it, but you haven't used it yet.
Average acceleration = (change in velocity) divided by (total time).
Change in velocity = (end value) minus (start value)
Change in velocity = (20m/s) - 0
Change in velocity = 20 m/s
Time = 10 s
Average acceleration = (20m/s)/(10s)
Average acceleration = 2 m/s^2
Answer:E
=
252
J
Explanation:
The total mechanical energy of an object or system is given by:
E
m
e
c
h
=
K
+
U
Where
K
is the kinetic energy of the object and
U
is the potential energy of the object. The carriage, sitting motionless at the top of the hill, has only potential energy in the form of gravitational potential energy.
Gravitational potential energy is given by:
U
g
=
m
g
h
Where
m
is the mass of the object,
g
is the gravitational acceleration constant, and
h
is the height of the object above some specific reference point, in this case the ground
21
m
below.
The weight of a stationary object at the surface of the earth is equal to the force of gravity acting on the object.
W
=
→
F
g
=
m
g
We are given that the carriage weighs
12
N
, therefore
m
g
=
12
N
.
U
g
=
12
N
⋅
21
m
⇒
U
g
=
252
N
m
=
252
J
Answer link
Explanation: