Serena is mixing a material into a beaker filled with liquid. She notices that the material seems to disappear into the liquid.
2 answers:
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Answer:
T_final = 279.4 [°C]
Explanation:
In order to solve this problem, we must use the following equation of thermal energy.
where:
Q = heat = 9457 [cal]
m = mass = 79 [g] = 0.079 [kg]
Cp = specific heat = 0.5 [cal/g*°C]
T_initial = initial temperature = 40 [°C]
T_final = final temperature [°C]
Answer:
Approximately upwards (assuming that
.)
Explanation:
External forces on this astronaut:
- Weight (gravitational attraction) from the earth (downwards,) and
- Normal force from the floor (upwards.)
Let denote the magnitude of the normal force on this astronaut from the floor. Since the direction of the normal force is opposite to the direction of the gravitational attraction, the magnitude of the net force on this astronaut would be:
.
Let denote the mass of this astronaut. The magnitude of the gravitational attraction on this astronaut would be
.
Let denote the acceleration of this astronaut. The magnitude of the net force on this astronaut would be
.
Rearrange to obtain an expression for the magnitude of the normal force on this astronaut:
.