physics chapter 3 Flashcards
what is mass
mass is a measure of the quantity of matter in an object at rest relative to the observer.
what is weight
weight is the gravitational force on an object that has mass
what is a gravitational field
a gravitational field is a region of space in which a mass exert a force of attraction on another mass
what is gravitational field strength
gravitational field strength (g) is defined as the gravitational force acting on it
what is the formula to calculate the gravitational field strength
g = weight in newtons / mass of an object in kg
how are mass and weight related
from the equation g=w/m, thus the weight of gravitational force (w) acting on an object is directly proportional to its mass (m)
what is the gravitational field strength in g near its surface on earth
9.8 N/ kg
what is a common weighing instrument to measure weight
spring balance
what is a common measuring instrument used to measure mass
top pan balance
what are some of the differences of mass and weight
mass
- amount of matter
- scalar quantity
- commonly measured in grams or kilograms
- independent of the gravitational field strength
- measured with a top pan balance
weight
- gravitational force
- a vector quantity
- commonly measured in newtons
- dependent on the gravitational field strength
- measured with a spring balance
what is density
the density of a substance is defined as its mass per unit volume
how do we calculate density
p ( density) = (mass) m/ (volume )v
which units are commonly used to measure density
kilograms per cubic metres and grams per cubic centimetre
why does heavy steel ship float
a large ship is an object that is made up of more than one material. In addition to steel, it contains a large volume of air in various rooms and cabins. Therefore, we will have to consider the average density of the ship
write the procedure and each step to find the density of a regular shaped solid
apparatus needed : rectangular wooden block, digital balance and ruler
procedure:
1. measure the length, height and width of one of the blocks. Multiply these to find the volume.
2. using the digital balance, find the mass of the block
3. calculate the density by dividing mass by volume
write the procedure and each step to find the density of a liquid
apparatus needed: measuring cylinder, digital balance
procedure:
1. measure the mass of an empty measuring cylinder
2. fill the measuring cylinder with 100ml of water and measure the mass of the measuring cylinder with water
3. find the mass of the water by subtracting the mass of an empty measuring cylinder by the measuring cylinder filled with water
4. read the volume of the water and calculate the density of the water by mass/volume
write the procedure and each step to find the density of an irregular shaped solid
apparatus needed: measuring cylinder, digital balance, irregular object, string, eureka can and beaker
procedure:
1. measure and record the mass of an irregular liquid
2. tie a piece of string around the object
3. place the eureka can on a block and place a beaker under the spout
4. fill the eureka can with water until water is coming out of the sprout. stop adding any more water and wait until it has stopped dripping from the spout
5. carefully remove the beaker and replace it with a measuring cylinder or a clean beaker
6. slowly lower the irregular shape into the eureka can until it is fully submerged
7. collect any of the water that comes out of the spout and record its volume
8. remember, the amount of water displaced is equal to the object’s volume
9. calculate the object’s density, by mass/volume
how is mass related to density
mass is directly proportional to its density. if mass increases, density increases, and if mass decreases the density decreases
what are the factors of sinking and floating
upthrust and density
what are some of the conditions for an object to sink
- substances that have lower densities than the liquid will float
- substances that have a higher density than the liquid sink
substances that float on liquid
has lower densities than the liquid
substances that sink in a liquid
has higher densities than the liquid
