Each increase in pressure of 100 atm decreases the melting point of ice by about 1.0¡ÆC.
Q. One possible explanation of why a skate moves smoothly over ice is that the pressure exerted by the skater on the ice lowers its freezing point and causes it to melt. The pressure exerted by an object is the force (its mass ¡¿ the acceleration of gravity, 9.8 m s-2) divided by the area of contact. Calculate the change in freezing point of ice when a skater with a mass of 75 kg stands on a blade of area 8.0 ¡¿ 10-5 m2 in contact with the ice.
Is this sufficient to explain the ease of skating at a temperature of, for example, -5¡ÆC (23¡ÆF)?
I don't really know how to approach this question?
To approach this question, you need to calculate the change in freezing point of ice caused by the pressure exerted by the skater standing on the blade. Here are the steps you can follow:
Step 1: Calculate the pressure exerted by the skater on the ice.
- Use the formula: Pressure = Force / Area
- The force can be calculated using the formula: Force = mass x acceleration due to gravity
- In this case, the mass is given as 75 kg and the acceleration due to gravity is 9.8 m/s^2.
- The area of the blade is given as 8.0 x 10^-5 m^2.
Step 2: Use the relationship between pressure and change in freezing point.
- The question states that each increase in pressure of 100 atm decreases the melting point of ice by about 1.0°C.
- Convert the pressure calculated in step 1 to atm units.
Step 3: Calculate the change in freezing point of ice caused by the pressure exerted by the skater.
- Use the relationship from step 2 to calculate the change in freezing point.
Step 4: Compare the change in freezing point to the given temperature (-5°C) to determine if it is sufficient to explain the ease of skating.
By following these steps, you can find the answer to the question.