1. Newton’s Laws of Motion
1st – An object will persist in is its state of constant velocity or rest until a net force accelerates it.
2nd – An object will accelerate in the direction of the net force. Its acceleration will be directly proportional to the net froce and inversely proportional to its mass.
3rd – For every action, there is an equal and opposite reaction.

2. Newton’s 1st Law accelerates
An object will persist in it’s state of constant velocity or rest until a net force changes it.
accelerates
An object at rest will remain at rest unless an unbalanced force accelerates it.
An object in motion at constant velocity will continue at constant velocity an unbalanced force accelerates it.

3. Unbalanced or Net Forces create changes in motion.
Newton’s 1st Law
An object will persist in it’s state of motion or rest until a net force changes it.
accelerates
Unbalanced or Net Forces create changes in motion.

4. Constant velocity means: Same speed Same direction
Newton’s 1st Law
An object will persist in it’s state of motion or rest until a net force changes it.
accelerates
Constant velocity means:
Same speed
Same direction

5. This law describes equilibrium: Constant velocity at rest
Newton’s 1st Law
An object will persist in it’s state of motion or rest until a net force changes it.
accelerates
This law describes equilibrium:
Constant velocity
at rest

6. Newton’s 2nd Law
An object will accelerate in the direction of the net force.
The acceleration of an object is directly proportional to the net force and inversely proportional to the mass.

7. Newton’s 2nd Law
An object will accelerate in the direction of the net force.
How much it accelerates depends on the amount of force and the mass of the object.
F = m * a
a = F/ m
m = F/ a

8. Newton’s 2nd Law
An object will accelerate in the direction of the net force.
Acceleration is directly proportional to the net Force.
a = F m a
If F goes down, a goes down.
If F goes up, a goes up.

9. Acceleration is inversely proportional to the net Force.
Newton’s 2nd Law
An object will accelerate in the direction of the net force.
Acceleration is inversely proportional to the net Force.
a = F m a
If m goes down, a goes up.
If m goes up, a goes down.

10. Newton’s 3rd Law
3rd – For every action, there is an equal and opposite reaction.
If object A exerts a force on object B, the force exerts by A on B is equal in magnitude and opposite in direction to the force B exerts on A.

11. This law describes force interactions between objects.
Newton’s 3rd Law
3rd – For every action, there is an equal and opposite reaction.
Forces occur in pairs.
This law describes force interactions between objects.

12. Newton’s 3rd Law
3rd – For every action, there is an equal and opposite reaction.
Forces occur in pairs.
When a car and a bird collide, the force on the car is the same as the force on the bird.

13. Newton’s Laws Third Law of Motion Second Law of Motion
Whenever one object exerts a force F on a second object , the second object exerts a force −F on the first object . F and −F are equal in magnitude and opposite in direction.
First Law of Motion
When a net force is applied to an object, it produces a proportional acceleration.
An object at rest will remain at rest until a net force accelerates it.
FNET = m*a
Σ F = m*a
Whenever a large mass and small mass interact, the forces on them will be equal but their resulting accelerations will be different.
at rest.
Forces are balanced, so object is in equilibrium.
V = 0 m/s a = 0 m/s2
When a net forces are balanced:
FNET = or Σ F = 0
F F
Forces between two objects
Forces on individual objects.
An object moving at constant speed in a straight line will keep moving at constant speed in a straight line until a net force accelerates it.
Equilibrium
Action- reaction outcomes.
a < a
constant velocity
When a net forces are not balanced:
FNET = or Σ F = 0
Forces are balanced, so object is in equilibrium.
V = 0 m/s a = 0 m/s2
The acceleration will be
directly proportional
to the net force
When F changes,
a changes the same way.
ACCELERATION
‘Not Equilibrium’
LAW OF INERTIA
“An object will keep doing what its doing until something changes it. “
The acceleration will be
inversely proportional
to mass.
When mass changes,
a changes the opposite way.

14. Forces and Newton’s Laws
1)     An automobile is at rest on a level road. Which of the following is false?
a)    No forces act on the car.
b)    The force due to gravity on the car is zero.
c)    The normal force is equal to the weight of the car.

15. 2) The car in the photo will remain at rest until:
a)    a force of any magnitude or direction is applied.
b)    a force greater than the weight is applied in a direction parallel to the road.
c)    a force greater than the friction force is applied in a direction parallel to the road.

16. Forces and Newton’s Laws
3)     The acceleration of an object is:
a)     directly proportional to the unbalanced force and mass.
b)     directly proportional to the unbalanced force and inversely proportional to the mass.
c)     inversely  proportional to the unbalanced force and directly proportional to the mass.

17. Forces and Newton’s Laws
4)     The SI unit of force is __________
and the SI unit of mass is _________.

18. Forces and Newton’s Laws
5)     A newton is equivalent to one:
a)    kg m /s
b)    kg m2/s
c)    kg m/s2
d)  kg m2/s2

19. Forces and Newton’s Laws
6)     Forces can
a)    Cause acceleration when they are unbalanced.
b)    be in equilibrium when they are balanced.
c)     act in pairs.
d) All of the above.

20. Forces and Newton’s Laws
7)     The direction of the net force in free body diagram shown is:
a)    forward
b)    backwards
c)    upward
d)    downward
2 N N 1N

21. Forces and Newton’s Laws
8)     On Earth, 1.0 kg physics book weighs:
a)    1.0 kg
b)    9.8 kg
c)    1.0 N
d)    9.8 N

22. Forces and Newton’s Laws
9)     How much force is required to give a 2000 kg car an acceleration of 3.0 m/s2 ?
a)     2000 N
b)    58800 N
c)    667 N
d)    6000 N

23. 10) The same force is applied to a 2000 kg car and a 4000 kg truck, both initially at rest.
a)     The car’s acceleration is twice that of the truck.
b)    The car and truck have the same momentum.
c)    The truck travels twice as far as the car.
d)    Both accelerate the same amount.

24. Forces and Newton’s Laws
 11)     If you were to travel to a different planet:
a)    your weight and mass would both change.
b)    your weight and mass would not change.
c)    your weight would change but your mass would not change.
d)    your weight would not change but your mass would change.

25. Forces and Newton’s Laws
12)     An unhappy individual is trying to slide a 100 kg desk across a wood floor. she applies an 800 N force parallel to the level floor, but the desk does not move. One can conclude that the force of static friction is:
a)    more than 800 N.
b)    more than 980 N.
c)    exactly 800 N.
d)    exactly 980 N.

26. 13)     A newton is a valid unit for
a)    mass.
b)    weight.
c)    acceleration.
d)    velocity.

27. Forces and Newton’s Laws
14)     A net force of 5000 N gives a certain acceleration to a 2000 kg car. How much net force is required to give the same acceleration to a 4000 kg truck?
a)    4000 N
b)    2000 N
c)    2500 N
d)    10,000 N

28. Forces and Newton’s Laws
15)     A package is sliding down a frictionless incline ramp. Its acceleration:
a)    is 9.8 m/s2.
b)    is less than 9.8 m/s2.
c)    is more than 9.8 m/s2.
d)    is none of the above.

29. Forces and Newton’s Laws
16)     An applied force causes a car to travel at a constant speed of 25 m/s.
a)    The applied force must be equal to the weight of the car.
b)    The applied force must be greater than the friction on the car.
c)    The applied force must be greater than the weight of the car.
d)    The applied force must be equal to the friction on the car.

30. Forces and Newton’s Laws
17)     The force of gravity acting on an object is called its
a)    weight.
b)    mass.
c)    acceleration.

31. Forces and Newton’s Laws
18)     When you stand on a typical bathroom scale with both feet it reads 80 pounds. If you stand on one foot it will read
a)    80 pounds.
b)    less than 80 pounds.
c)    more than 80 pounds.

32. 19)     A package dropped from an airplane encounters air resistance as it falls to the ground. Select the statement that best describes its motion as it falls. a)    The package falls at a constant velocity until it strikes the ground.
b)   The package accelerates increasing its speed of descent until it strikes the ground.
The package falls at a constant velocity at first, before beginning to accelerate.
The package accelerates until it reaches terminal velocity.

33. Forces and Newton’s LawsB   
20)     You are sliding two boxes across a frictionless floor by applying force F to box A as shown above. The force that box A exerts on box B is
a)    equal to F b)    greater than F c)    less than F.

34. 21)     The same force is applied to the same object on Earth and on the Moon. The acceleration is
a)    greater on the Earth.
b)    greater on the Moon.
c)    the same in both places.

35. Forces and Newton’s Laws
22)     John weighs 100 N on Earth and Mary weighs 100 N on the Moon.
a)    John’s mass is greater than Mary’s.
b)    Mary’s mass is greater than John’s.
c)    John and Mary have the same mass.

36. Forces and Newton’s Laws
23)     John weighs 100 N on Earth and Mary weighs 100 N on the Moon.
a)    John is a child and Mary is an adult.
b)    Mary is a child and John is an adult.
c)    John and Mary are both children.

37. Forces and Newton’s Laws
24)     A 10 kg box is hanging from two massless scales as shown:
a)    Scale A reads 10 kg and scale B reads zero.
b)    Scale A reads zero and scale B reads 10 kg.
c)     Scales A and B each read 5 kg.
d)    Scales A and B each read 10 kg.

38. 25) A 10 kg beam with uniform density is hanging as shown above.
A and B are
massless scales.
25)     A 10 kg beam with uniform density is hanging as shown above.
a)    Scale A reads 10 kg and scale B reads zero.
b)    Scale A reads zero and scale B reads 10 kg.
c)    Scales A and B may have different readings but the sum must be 10 kg.
d)    Scales A and B each read 10 kg.