We know 1
When the sun is low in the sky early in the mornings, trees form _________ __________.
long shadows.
Besides strength, or magnitude every force also has_______.
direction
The total forces acting on a body is ______ ______.
net force
Which of the following is a contact force?
gravity, magnetism, electrical, friction
friction
A pencil on a table is a _______ force.
balanced
Two forces acting together in the same direction is called _______ __________.
combined forces
True or False: Friction is a kind of force.
True
True or False:
A book sitting on a table has uniform motion.
True
A push or pull that acts on an object is __________.
Force
Yes or No:
Do you weigh less on Earth than in a spaceship orbiting 800 kilometers above Earth.
No
_____ happens when two materials rub against each other.
Friction
The rate at which the speed or the direction of motion of an object changes over time is its ________.
acceleration
A force of 40 N accelerates a 2kg object. How much force is needed to give the same acceleration to a 40 kg object.
400 N
A ball rolled across four different surfaces with the same force. grass, cement, tile floor, wood floor. Which surface will slow the ball the most?
Grass
Electric and magnetic forces act on different objects by either _________ or ________ them.
push or pulling
What happens when an object accelerates?
it's speed or direction changes.
What is the formula for Newton's 2nd Law of motion describing the relationship between force, mass, and acceleration?
f=mxa or force = mass times acceleration
When you ride a roller coaster, what makes your body rise out of its seat at the top of a hill?
Inertia
Finish the sentence correctly,
The greater the net force acting on an object,
the greater the acceleration of the object.
If you and a friend are playing tug of war and your friend pulls you across the line it is known as an ______ force.
unbalanced
Two tractors are pulling a tree in opposite directions but with the same strength it is called a _______ force.
balanced
Newton's First Law of Motion states
An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force.
Newton's 2nd Law of motion states
the greater the mass of an object, the greater the force needed to change its motion.
Newton's 3rd Law of motion states
"for every action, there is an equal and opposite reaction,"
What does gravity do?
pulls things toward the center of the Earth.