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Ch. 2 Forces Test
Ch. 2 Forces Test
42
Science
7th Grade
03/15/2013

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Term
Give an example of exerting a force.
Definition
Example: A carpenter hammering a nail.
Term
What happens when two forces act in the same direction?
Definition
They add together.
Term
The tendency of an object to resist change in its motion is known as________.
Definition
Intertia.
Term
The greater the mass of an object, ___________.
Definition
The greater its inertia.
Term
One way to increase acceleration is by ___________.
Definition
decreasing mass.
Term
The force that one surface exerts on another when two rub against each other is called_________.
Definition
Friction
Term
Give an example of rolling friction.
Definition
Example: Bike tires on the road as you ride.
Term
When the only force acting on a falling object is gravity, the object is said to be ____________.
Definition
in free fall
Term
Air resistance is a type of __________.
Definition
Friction.
Term
The force of gravity on a person or object at the surface of a planet is known as__________.
Definition
Weight
Term
The law of universal gravitation states that any two objects in the universe_______.
Definition
Attract each other.
Term
Forces can be added together only if they are________.
Definition
acting on the same object.
Term
The product of an object's mass and velocity is called its_________.
Definition
momentum
Term
According to the law of conservation of momentum, when two items collide in the absence of friction, _______.
Definition
momentum is not lost.
Term
Any force that causes an object to move in a circle is called a ______________.
Definition
centripetal force
Term
In physical science, a push or a pull is called a ________.
Definition
force
Term
The momentum of an object is in the same direction as its _____________.
Definition
velocity
Term
How can you increase the momentum of an object?
Definition
By increasing its mass.
Term
The amount of matter in an object is called its ____________.
Definition
mass
Term
Give an example of increasing friction intentionally.
Definition
Example: Throwing sand on an icy driveway.
Term
The force that pulls falling objects toward Earth is called_________.
Definition
Gravity.
Term
Objects falling through the air experience a type of friction called ____________.
Definition
air resistance
Term
According to Newton's third law of motion, when a hammer strikes and exerts a force on a nail, the nail________.
Definition
exerts an equal force back on the hammer.
Term
The SI unit for force is the _______.
Definition
newton
Term
Balanced forces acting on an object __________.
Definition
never change the object's motion.
Term
The total momentum of a group of objects is conserved unless _________________.
Definition
outside forces act on the objects.
Term
True or False: When the only force acting on a falling object is air resistance, the object is said to be in free fall.
Definition
False--> gravity
Term
True or False: A rocket will move upward as long as the thrust is greater than the force of gravity.
Definition
True!!!
Term
True or False: The force that keeps a satellite in Earth orbit is always directed away from the center of Earth.
Definition
False---> toward
Term
The overall force of an object after all the forces are added together is called the ______ force.
Definition
net
Term
Unbalanced forces acting on an object produce a change in the object's ___________.
Definition
Motion
Term
A measure of an object's _____ is a measure of the object's inertia.
Definition
mass
Term
One _______ is the force required to accelerate 1 kilogram of mass at 1 meters per second per second.
Definition
newton
Term
A person traveling in a car that stops suddenly keeps moving forward due to _______.
Definition
inertia
Term
Wet pavement is more slippery than dry pavement because the force needed to overcome ________ friction is less than the force needed to overcome sliding friction.
Definition
fluid
Term
The downward force acting on an object in free fall is the force of ________.
Definition
gravity
Term
A(n) ________ is an object that is thrown.
Definition
projectile
Term
The metric unit that is most often used to describe weight is the _________.
Definition
newton
Term
The force of gravity between you and Earth is greater than the force of gravity between you and a car because Earth has more _____ than a car.
Definition
mass
Term
As the distance beween two objects decreases, the gravitational force between them ________.
Definition
increases
Term
Fricton acts in a direction _______ to an object's direction of motion
Definition
opposite
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