Chapters 5-6 Test Review

1
Chapters 5-6 Test Review

• Forces Motion

2
Forces

• a push or a pull
• A force can start an object in motion or change
  the motion of an object.
• A force gives energy to an object

3
What is a push or a pull?

• A. canopy
• B. force
• C. gruff
• D. scoff

4
Representing forces

• We often use arrows.
• Larger the arrow, the greater the force
• Combined balanced forces equal zero
• Normal force the force acting perpendicular on
  an object in contact with another object.

5
What prevents a book on a table from accelerating
downward?

• A. gravity is pulling on the table
• B. the table is pushing back with a larger force
• C. the table is pushing back with an equal force
• D. air

6
Balanced Forces

• Forces opposite in direction and equal in size.
• Net result no change in motion.

7
Unbalanced Forces

• Unbalanced forces will cause an object to change
  motion.

8
When an unbalanced force acts on an object,

• A. the objects motion does not change.
• B. the object accelerates.
• C. the object will stop.
• D. the inertia of the object increases.

9
The net forces acting on any object will cause it
to

• A. keep moving at the same speed.
• B. accelerate.
• C. stop.
• D. swim like a fish.

10
If a 10 N net forces acts on a 20 kg object it
will accelerate at (af/m)

• A. 5 m/s
• B. 200 m/s
• C. 0.5 m/s2
• D. 2 m/s2

11
What force is needed to accelerate a 4 kg ball at
12 m/s2? (af/m)

• A. 3 m/s
• B. 48 m/s
• C. 0.75 N
• D. 48 N

12
GRAViTY

• The pull of one body of mass on another.

13
What two factors change gravitational force?

• A. Speed and direction.
• B. Mass and distance.
• C. Mass and velocity.
• D. Speed and momentum.

14
Weight is a force that depends on gravity and

• A. mass.
• B. acceleration.
• C. friction.
• D. force.

15
Acceleration due to gravity

• All objects fall at the same rate, regardless of
  their mass or weight
• The acceleration due to gravity on earth is about
  9.8 m/sec2.
• This value will change with elevation and
  location on earth.

16
Terminal Velocity

• After a period of free fall, the force of gravity
  will be canceled by the force of air friction and
  objects will travel at a constant velocity

17
The forces acting on a falling leaf are gravity
and air resistance. If the leaf falls at a
constant rate,

• A. forces are balanced.
• B. forces are unbalanced.
• C. the world will end.
• D. a leaf never falls at a constant rate.

18
Newtons First Law of motion

• An object at rest will remain at rest and an
  object in motion will remain in motion unless
  acted upon by an outside force.
• Often referred to as the Law of Inertia.
• (the property of matter that resists any change
  in motion)

19
The property of matter that resists changes in
motion is called

• A. centripetal motion.
• B. friction.
• C. inertia.
• D. projectile motion.

20
Inertia is related to

• A. speed.
• B. weight.
• C. mass.
• D. motion.

21
An orange might roll off your cafeteria tray when
you stop suddenly because of

• A. the balanced forces acting on the orange.
• B. the friction forces acting on the orange.
• C. the centripetal force acting on the orange.
• D. the oranges inertia.

22
Newtons Second Law of Motion

• The force of a moving object is directly
  proportional to the objects mass and
  acceleration.
• The most important of Newtons laws.

Force mass x acceleration
23
According to Newtons second law, the
acceleration equals the net force divided by the
objects

• A. mass.
• B. velocity.
• C. momentum.
• D. weight.

24
Weight and Mass

• MASS
• The measure of inertia of an object.
• The amount of matter in an object
• Stays constant with changes in location
• A scalar

• WEIGHT
• A measure of the force of gravity acting on an
  object.
• Measured in newtons.
• Changes with changes in location.
• A vector

25
Your weight equals your

• A. mass
• B. mass divided by the net force acting on it.
• C. mass times acceleration due to gravity.
• D. mass times your speed.

26
Why is your weight less on the moon?

• A. Mass changes on the moon.
• B. Gravity is less on the moon.
• C. Gravity is greater on the moon.
• D. Weight never changes, only mass changes.

27
Newtons Third Law of Motion

• For every action there is an equal and opposite
  reaction, or
• All forces occur in pairs
• examples

28
Newtons third law of motion describes

• A. action and reaction forces.
• B. centripetal forces.
• C. balanced forces.
• D. net force.

29
When one object exerts a force on another,

• A. the objects will always move as a result of
  the interaction.
• B. an equal and opposite force is exerted back on
  it by the other object.
• C. the objects will never move due to the forces
  cancelling each other out.
• D. one object will always exert a greater force
  on the other object.

30
Momentum

• All moving objects have momentum.
• How hard is it to stop and object.
• It is the product of an objects mass and
  velocity.
• the mass matters
• the speed matters
• p mv

31
What is the momentum of a truck at rest?

• A. Zero
• B. Equal to the mass.
• C. Equal to the weight.
• D. Trucks do not need to rest.

32
If a golf ball and marble are rolling at the same
speed, which has a greater momentum?

• A. Golf ball
• B. Marble
• C. They have the same.
• D. I lost my marbles a long time ago!

33
The product of an objects mass and velocity is
its

• A. centripetal force.
• B. net force.
• C. momentum.
• D. weight.
• P mv