S4 Phy Mechanics Force and Motion WorkSheet3 LC
S4 Physics
Mechanics
Force and Motion
WorkSheet 3
1.
Newton’s First Law of Motion (the Law of INERTIA)
Newton’s first law of motion states that a body will ______________in its
state of motion (either at rest, or moving at a uniform velocity) if there is
no___________ force acting on it.
(A) Tricks with inertia
(i)
Coin on a cardboard
The coin remains at_____________ on the finger when the cardboard is
flicked away.
(ii)
Stack of coins
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S4 Phy Mechanics Force and Motion WorkSheet3 LC
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The rest of the stack of coins do not____________. They stay vertically
when the bottom one is striken away.
(iii)
Toilet paper
The piece of toilet paper is torn off and the roll remains
_________________when the paper is pulled by a jerk.
The roll of toilet paper rotates____________ when the paper is
pulled_____________.
The above phenomena demostrate that objects are____________ to move.
We say they have ___________________.
(B) Inertia and Mass
Inertia can be _______________ by mass. The greater the mass
_____________ the inertia will be. A body of greater mass will have a greater
inertia. It has a greater ______________ to maintain its state of motion.
Mass is a measure of the _______________of matter inside a body.
Examples:
(i)
A big ship is more difficult to move and stop than a ca because the ship
has a larger _______________.
(ii)
A fat woman is more likely to thrown out of a car in accident because
she is more hard to stop because she has a larger ___________ and
hence a greater ________________.
Therefore, for saftly purposes, seat belt and head rest are installed in cars.
When the car stopped suddenly, the passenger moves on due to ____________
and ___________down by the pull from the seat belt.
When the car bumped at the back, push from the head rest accelerates the head
and neck forwards to prevent injury from jerk which stems from ____________.
S4 Phy Mechanics Force and Motion WorkSheet3 LC
2.
Addition and Resolution of Forces
(A) Addition of forces
Forces are _____________.
They have both _____________ and _____________.
In adding forces, the _____________ of the forces as well as the
magnitude must be take into consideration .
The method of adding forces is called the ___________________.
The sum of forces is called the ________________ force.
(i)
Forces in a straight line
In this case, one direction is taken as ____________and the other as negative.
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S4 Phy Mechanics Force and Motion WorkSheet3 LC
(ii)
Forces at an angle
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S4 Phy Mechanics Force and Motion WorkSheet3 LC
There are numerous ways to resolve a vector, but resolved into two
_______________ components are more useful in the sense that they are
independent. (that means they can be handled separately)
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