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100
What is is the speed of a soccer ball that moves 50 meters in 10 seconds?
5 meters per second
100
What is a device that replaces human effort?
a machine?
100
What type of force allows you to stand up from a chair? opposite, equal, balanced, unbalanced
unbalanced
100
Why are the brakes on an adult's bike stronger than the brakes on a child's bike?
an adult rider will have more momentum and will need more friction to slow them down
100
What is motion?
a change in position over time
200
How can the motion of an object be described?
change in position over time
200
What is needed to operate a machine?
energy
200
A ball has two forces acting on it. One force is pushing it to the right at 6 N and another larger force is pushing it to the left at 8 N. What direction will the ball move and what is the Net force?
Left 2 N
200
How must the forces of the wind and gravity interact for a kite to fly in the air.
the wind must be greater than the force of gravity
200
What is a change in speed or direction of an object's motion?
acceleration
300
The motion of an object can be understood by examining what? a. the magnetic forces that are acting on that object b. the object's inertia c. all of the forces that are acting on that object d. the gravity that is acting on the object
C. all of the forces that are acting on that object?
300
Why does a machine that lifts boxes off the ground need energy?
to overcome the force of gravity
300
What is the tendency of an object to remain at rest or in motion called?
inertia
300
Which kind of tool makes work easier and has few or no moving parts?
a simple machine
300
A person in a head-on collision who is not wearing a seat belt continues to move forward at the original speed of the car because of ________ .
inertia
400
What is a force?
a push or pull
400
forces are measured in units called:
newtons
400
What is changed by how fast an object is moving and how much mass that object has?
momentum
400
What is an inclined plane that is wrapped around a cylinder also known as?
a screw
400
For every action there is _____________________ .
an equal but opposite reaction
500
The forward motion of a shark is caused by which force? thrush, pull, drag, lift
thrust
500
What are forces that have a net of zero called?
balanced
500
A soccer ball rolls across a grassy field and comes to a stop. What caused the ball to stop?
friction
500
What are two inclined planes placed back to back called? They are used to split things.
a wedge
500
Newton's first law of motion states that an object stays at rest unless _________________ .
an unbalanced force acts on it.