True/False
Forces that are equal in size but opposite in direction are called UNBALANCED forces.
False- Balanced
According to Newton's second law of motion, ____.
a. F = mvc.
b. a= Fnet /m
c. F = m/a
d. F = ma
The unit of force is ____.
a.m/s
b.the hertz
c.the joule
d.the newton
D
Acceleration depends on which to factors?
Mass and Net force
What forces are when the net force on an object is zero
Unbalanced forces
Earth exerts AN UNBALANCED force on a ball into the air.
True
Forces that are equal in size but opposite in direction are ____.
a.balanced forces
b.frictional forces
c.inertial forces
d.net forces
A
The statement "for every action, there is an equal but opposite reaction" is a statement of ____.
a.the law of conservation of momentum
b.Newton's first law
c.Newton's second law
d.Newton's third law
D
You push on a crate with a force of 10 N to the right, and your friend pushes on the crate with a force of 25 N to the left. Describe and explain the motion of the crate.
The crate accelerates to the left because there is a net force of 15 N acting to the left.
The combination of all forces acting on an object
net force
Acceleration is caused by both balanced and unbalanced forces
False - Unbalanced
An unbalanced force acting on an object causes it to ____.
a.move at constant speed
b.continue in a straight line
c.not change its velocity
d.accelerate
D
Whenever a body is in motion, there is always ____ to oppose the motion.
a.friction
b.inertia
c.gravity
d.acceleration
A
The crate accelerates to the left because there is a net force of 15 N acting to the left.
The larger crate will need more net force because force is directly proportional to mass
law that states: if the net force on an object is zero; an object at rest remains at rest, or, if the object is moving, it continues to move in a straight line with constant speed.
Newton's 1st law of motion.
The relationship among force, mass, and acceleration is stated in ____.
a. the law of conservation of momentum
b. Newton's 1st law of motion
c. Newton's 2nd law of motion
d. Newton's 3rd law of motion
C
When two birds are pulling on a worm and the worm moves toward the first bird, you know that the forces are ____.
a.long-range
b.action-reaction
c. unbalanced
d. balanced
C
A student sees a motionless ball resting on a table. Describe the forces acting on the ball.
Gravity is creating a downward force that is equal to the force of the table pushing up.
A pushing force exerted between an object and a surface
What is frictional force
An object with the mass of 9.0 kg has an acceleration of 3 m/s2. The fore acting on it is 3N.
False- 27N- 9kg/3m/s2= 27N
A 300-N force acts on a 25-kg object. The acceleration of the object is ____.
a.7,500 m/s2
b.300 m/s2
c.25 m/s2
d.12 m/s2
D
A 3,000-N force gives an object an acceleration of 15 m/s2. The mass of the object is ____.
a.45,000 kg
b.1,500 kg
c.200 kg
d.15 kg
C
A girl is holding a block. If the block isn't moving, what forces are acting on it? What do you know about them?
The forces of the girl's hands and the force of gravity are acting on the block.
The force between two objects that keeps an object at rest
force of static friction