midterms qna

Question 1

How do you relate buoyant force to the density of the metal sample?

Answer 1

metal density is greater than the liquid density = metal sinks (BF is too week to hold it up)

metal density is lower than the liquid density = metal floats (BF is strong enough to hold it up)

Question 2

How do you relate buoyant force to the density of the liquid?

Answer 2

the BF is stronger when the density of the liquid is denser

Question 3

what will happen to the object if its density is
equal to the fluid:
greater than that of the liquid:
less than that of the liquid:

Answer 3

equal to the fluid:
the object will neither sink nor float
stay suspended in the fluid

greater than that of the liquid:
will sink cos heavier than the fluid displaces

less than that of the liquid:
will float as it is lighter than the fluid it displaces

Question 4

How do you relate change in temperature with the expansion of metals?

Answer 4

temp increases, metal expands (longer)
the amt it expends depends on how much the temp increases
the higher the temp changes, the more the metal expands

Question 5

What causes the expansion of metals when heated?

Answer 5

heating makes the metal’s atom vibrate more, pushes them slightly further apart
= increased vibration and separation btwn atoms cause the metal to expand

Question 6

What does it mean when a certain material has a high or low specific heat?

Answer 6

high specific heat:
absorb a lot of heat w/o getting v hot

low specific heat:
heats up quickly even w a small amt of heat

*this tell us how much energy is needed to raise the temp of the material

Question 7

When measuring latent heat, why should your final temperature be the minimum temperature reached by the calorimeter?

Answer 7

the final temp shld be the lowest bcs this is when the ice has fully melted and absorbed the max. heat it can
this point helps accurately measure the total heat needed to melt the ice

Question 8

How is the law of conservation of heat energy observed in the experiment?

Answer 8

heat lost by the warmer objects equals the heat gained by the cooler object
this exchange shows that heat energy is conserved, just transferred from one to the other

Question 9

What determines the direction of heat flow?

Answer 9

heat alw flows from a hotter object to a cooler one until both reach the same temp
the diff in temp btwn 2 object drives the heat flow