Answer:
the final temperature = 74.33°C
Explanation:
Using the expression Q = mcΔT for the heat transfer and the change in temperature .
Here ;
Q = heat transfer
m = mass of substance
c = specific heat
ΔT = the change in temperature
The heat Q required to change the phase of a sample mass m is:
Q = m
where;
is the latent heat of vaporization.
From the question ;
Let M represent the mass of the coffee that remains after evaporation is:
ΔT = 
where;
m = 2.50 g
M = (240 - 2.50) g = 237.5 g
= 539 kcal/kg
c = 1.00kcal/kg. °C
ΔT = 
ΔT = 5.67°C
The final temperature of the coffee is:
ΔT
where ;
= initial temperature = 80 °C
= (80 - 5.67)°C
= 74.33°C
Thus; the final temperature = 74.33°C
Answer:
a) 
, b) From east to west.
Explanation:
Vectorially, the magnetic force can be calculed by the following formula:
The cross product is:
a) The magnitude of the magnetic force is:
b) The direction of the magnetic force is:
From east to west.
Answer:
Answer below!!!!
Explanation:
Convection is the transfer of thermal energy by particles moving through a fluid.
Hope I Helped!!!
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Answer:
d- Earth revolves around the sun.
Explanation:
Earth rotation can be defined as the amount of time taken by planet earth to complete its spinning movement on its axis.
This ultimately implies that, the rotation of earth refers to the time taken by earth to rotate once on its axis. One spinning movement of the earth on its axis takes approximately 24 hours to complete with respect to the sun.
On the other hand, earth revolution can be defined as a complete trip along a path around the sun. This path is known as an orbit and it typically takes the Earth 365¼ days to complete it's journey around the Sun.
When a constellation (stars) changes its position in the sky, at the same time of the evening and over a period of several weeks; it ultimately implies or is an evidence that Earth revolves around the sun.
Answer:
2.87 km/s
Explanation:
radius of planet, R = 1.74 x 10^6 m
Mass of planet, M = 7.35 x 10^22 kg
height, h = 2.55 x 10^6 m
G = 6.67 x 106-11 Nm^2/kg^2
Use teh formula for acceleration due to gravity
g = 1.62 m/s^2
initial velocity, u = ?, h = 2.55 x 10^6 m , final velocity, v = 0
Use third equation of motion
0 = v² - 2 x 1.62 x 2.55 x 10^6
v² = 8262000
v = 2874.37 m/s
v = 2.87 km/s
Thus, the initial speed should be 2.87 km/s.
