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.
Answer:
Explanation:
System of forces in balance
ΣFx = 0
ΣFy = 0
∑MA = 0
MA = F*d
Where:
∑MA : Algebraic sum of moments in the the point (A)
MA : moment in the point A ( N*m)
F : Force ( N)
d : Horizontal distance of the force to the point A ( N*m
Forces acting on the beam
T₁ = 620 N : Tension in cable 1 ,at angle of 30° with the vertical on the left
T₂ : Tension in cable 2, at angle of 50.0° with the vertical on the right.
W : Weight of the beam
x-y T₁ and T₂ components
T₁x= 620*sin30° = 310 N
T₁y= 620*cos30° = 536.94 N
T₂x= T₂*sin50°
T₂y= T₂*cos50°
Calculation of the T₂
ΣFx = 0
T₂x-T₁x = 0
T₂x=T₁x
T₂*sin50° = 310 N
T₂ = 310 N /sin50°
T₂ = 404.67 N
Calculation of the W
ΣFy = 0
T₂y+T₁y-W = 0
(404.67) *cos50° + 536.94 = W
W= 260.12+ 536.94
W= 797.06 N
Location of the center of gravity of the beam
∑MA = 0 , point (A) (point where the cable 2 of the right is located on the beam)
T₁y(5)-W(d) = 0
T₁y(5) = W(d)
d = T₁y(5)/W
d = 536.94(5) / 797.06
d = 3.37m
The center of gravity is located at 3.37m measured from the right end of the beam
The correct answer is C.
W=force into distance.
Option B states that "balanced forces act on on object and cause movement in direction of these force" which is against the laws of physics.
Option A is wrong because work is the product of force into distance,its not time.
Option D says that work is distance over time,which is wrong as:
speed=distance/time
So your left with option C
Answer:
the speed in -y
Explanation:
For this exercise we must use the right hand rule. The motion of a positive charge is given by.
Thumb points in the direction of speed
fingers extended in the direction of the magnetic field, + z axis
the palm in the direction of the force, as the charge is negative in the opposite direction of the force, axis + x
therefore the thumb is in the direction - y
the speed in -y
The answer would be velocity because its stating the speed and direction of the car.