Transcript forces

The Man’s
Jeopardy
Learning Objectives (Big Ideas)
1. Analyze an object’s motion and be able to
determine distance, instant & average speed, or
acceleration.
2. Describe how the various balanced and
unbalanced forces can have an effect on an
object’s motion.
3. Apply Newton’s Laws to real world examples.
4. Analyze the methods by which machines make
work easier.
5. Examine situations where kinetic energy is
changed into potential energy (and vice-versa).
RULES
1. There will be round robin play and all
questions will be all-play.
2. The teams who answers correctly win the
point value of the question.
3. If a team answers a daily double
incorrectly, then that team will lose the
number of points they bid.
4. There are no daily doubles available. Let’s
play
Motion
Forces Work & Energy
Machines
100
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300
Final Jeopardy
Motion for 100
What is the distance traveled at the 4 s
mark?
40 m (+ or – 2 m)
Motion for 200
Draw a distance-time graph for an object
that is not moving at all.
Straight horizontal line on a distance vs.
time graph
Motion for 300
Draw a speed-time graph for an object
traveling at a constant speed.
Graph should be a straight horizontal line
indicating the same speed over a period
of time for a speed-time graph.
Motion for 400
Draw a distance-time graph for an object
traveling at a constant speed.
Graph should be a straight line slanted
up and to the right or down and to the
right (with distance on the y-axis and
time on the x-axis)
Motion for 500
Draw a speed-time graph showing an object
slowing down.
Graph should be a slanted line going down and to the
right on a speed-time graph.
Forces for 100
Which of the following would exert the greatest
force: a truck accelerating at 5 m/s/s, a small stone
accelerating at 6 m/s/s, or a person accelerating at
5.5 m/s/s. Explain your answer.
The truck because its greater mass has a greater
effect on the force it would exert than the
slightly higher accelerations of the person and
the stone.
Forces for 200
Explain why a person can sometimes fly
backward when kicking another person.
Hint- Newton’s 3rd Law.
The action force is the kick, while the equal
and opposite reaction is the body of the
person who’s being kicked pushing
back on the kicker.
Forces for 300
Why are larger people unable to move as
quickly as lighter people?
More force is required to accelerate a
heavier mass.
Forces for 400
Explain why your body moves backward
when a car first takes off.
Your body is at rest and attempts to
remain at rest (due to your inertia).
Forces for 500
Markie & Suzie conduct an experiment to
determine how mass affects the force exerted by
an object. They choose to accelerate objects down
a ramp. They both believe that heavier objects
will exert more force. What is their hypothesis?
What is the independent variable? What is the
dependent variable? What are 2 constants?
Hyp.- Heavier objects exert more force
Ind. Var.- Mass of the objects
Dep. Var.- Force exerted
Constants- Same ramp height/incline, same
acceleration, same object, same position of
release on the ramp
Work & Machines for 100
Which class of lever is the input force
opposite the output force? Is this the class
that pliers belong to?
1st class
Yes, b/c the fulcrum is in the middle.
Work & Machines for 200
How can you increase the M.A. of a pulley
system?
Add more pulleys to create more sections of
rope.
Work & Machines for 300
Suppose the input force for a screwdriver is 15 N,
then which of the following could be the output
force: 0 N, 10 N, 15 N, or 30 N? Also, how does
the M.A. compare to 1?
30 N (output is greater than input, M.A. > 1)
Work & Machines for 400
Which of the following would be the best example
of a compound machine: scissors, ruler,
wheelbarrow, or door stopper? List 2 types of
simple machines that make up the compound
machine.
Wheelbarrow: wheel & axle and lever (2nd
class)
Work & Machines for 500
Explain how a screwdriver works.
The input force over the wheel (handle) travels a
greater distance than the larger output force
over the axle (metal rod).
Energy for 300
If your throw a ball up in the air, how do the PE and
KE change as the ball goes up and then comes back
down? Explain your answer.
PE increases as the ball goes up because it is higher
off of the ground while the KE decreases until the
ball starts to gain speed as it goes back toward the
ground. As the ball goes down, the KE increases
and the PE decreases (lower height).
Forces
Newton’s Cradle demonstrates how momentum
(and energy) can be transferred between
objects. However, after a period of time, the
metal spheres do not bounce as high and
eventually stop moving. Explain why this
occurs.
Friction between the spheres as well as the air
around the cradle cause the momentum and
energy to be “lost”.