Force and Motion
Force and Net forceForceWe learned about the motion of
objects.That there are three types of motion: speed, velocity, and
acceleration.Also, how to calculate speed: Speed= d/tBut, what
causes an objects motion?Forces create or prevent motion.ForceForce
is a push or a pull Examples: gravity, friction, magnetic,
electrical. Forces can be balanced or unbalanced.Balanced forces
have no change in motion.Unbalanced forces create change in
motion.Forces can be measured with a spring scale.Newton (N) is the
unit of force.ForceSpring scale (N):
Examples of Balanced forces
Unbalanced forces
More Unbalanced forces
Net Force
Net ForceThe Net force is the sum (total) of all forces acting
or applied to an object.
Net Force
Calculating Net Force
When forces move in opposite directions you subtract to find the
net force.Unbalanced forces creates motion/movement.Calculating Net
Force
When forces move in opposite directions you subtract to find the
net force.Balanced forces have no motion.Calculating Net Force
When forces move in the same direction you add to find the net
force.Unbalanced forces creates motion/movement.Force ArrowsForces
can be shown with force arrowsThe size of and length of the arrow
show its strength (magnitude).A longer arrow = A stronger
arrow30N10N100NAny Questions?
Practice Problem Juan pushes a box with a force of 5N to the
left. Brandon pushes the same box from the opposite side with a
force of 3N to the right. What happens to the box?A. The box moves
to the right with a force of 8N. B. The box does not move forces
are balanced.C. The box moves to the left with a force of
2N.Answer: Forces are opposite and must be subtracted. 5N-3N = 2N
towards the left (larger force)Speed ProblemForces that act on
objects can affect their speed and direction.
A car is traveling down the street in direction A. Which of the
forces shown in the figure above would affect ONLY the speed of the
car?
A. 1 B. 2 C. 3 D. 4
17Speed ProblemForces that act on objects can affect their speed
and direction.
A car is traveling down the street in direction A. Which of the
forces shown in the figure above would affect ONLY the speed of the
car?
A. 1 B. 2 C. 3 D. 4
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