Science 20 Unit B Final Test
What I Need to Know
This test will be a 30 MC test 5 written calculations
20–B1.1k distinguish between scalar and vector quantities, including distance and displacement, speed
and velocity
20–B1.2k define velocity and acceleration as v d / t and a v / t , respectively
20–B1.3k compare and contrast displacement in uniform motion and uniformly accelerated motion
Skills: analyze position-time and velocity-time graphs to infer the relationships among displacement,
velocity and acceleration
20–B2.1k define momentum as a vector quantity equal to the product of the mass and velocity of an
object (p= mv )
20–B2.2k apply the law of conservation of momentum to one-dimensional collisions and explosions
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20–B2.3k define change in momentum as impulse p mv Favet relate impulse to acceleration and
Newton’s second law of motion and apply the concept of impulse to explain the functioning of a variety
of safety devices
20–B2.4k explain how an unbalanced force causes change in motion and apply Newton’s first law of
motion to explain an object’s state of rest or uniform motion;
20–B2.5k apply Newton’s second law of motion and use it to relate force, mass and motion;
20–B2.6k apply Newton’s third law of motion to explain the interaction between two objects;
Newton’s Laws
According to Newton's first law...
An object at rest will remain at rest unless acted on by an
unbalanced force. An object in motion continues in motion
with the same speed and in the same direction unless acted
upon by an unbalanced force.
This law is often called
"the law of inertia".
What does this mean?
This means that there is a natural
tendency of objects to keep on
doing what they're doing. All objects resist changes
in their state of motion. In the absence of an
unbalanced force, an object in motion will maintain
this state of motion.
According to Newton's second law...
Acceleration is produced when a force acts on a mass. The
greater the mass (of the object being accelerated) the greater
the amount of force needed (to accelerate the object).
What does this mean?
Everyone unconsiously knows the
Second Law. Everyone knows that
heavier objects require more force
to move the same distance as lighter objects.
According to Newton's third law...
For every action there is an equal and opposite re-action.
What does this mean?
This means that for every force there is a reaction force that is equal
in size, but opposite in direction. That is to say that whenever an
object pushes another object it gets pushed back in the opposite
direction equally hard.
The 6 Steps:
Each written calculation is marked out of 6 for the following 6 steps
1.
2.
3.
4.
5.
6.
What you know
What you don’t know
Formula
Substitution
Answer
Picture or conversion
NOTE: it is always a good idea to start physics problems with a picture so that you can better understand
what the question is asking or stating