3.1, 3.2, 3.3 Forces, FBD, Net Forces
3.4 First Law
3.5 - Second Law
3.6 Weight vs Mass
3.7 Third Law + Bonus Qs
100
Name two contact forces
Various Answers
100
What is Inertia:
A- The speed at which objects fall
B - Friction of a rolling object
C - Object's resistance to change
D - Mass x Acceleration due to gravity
B
100
What is the formula to find force?
F = m x a
F = ma
100
Does mass change from place to place?
Does weight change from place to pace?
No
Yes
100
Newton's third law describes actions with equal and opposite ______.
Reactions
200
Draw a FBD for a book at rest on top of a table. Identify whether or not the forces acting on the book are balanced or unbalanced.
Balanced.
200
Which object has MORE inertia?
A shopping cart with a mass of 12 Kg OR a small hunk of metal with a mass of 20 Kg.
A small hunk of metal.
An osmium cube with sides 3.7 inches long would be 20 Kg or 45 pounds! And would cost $1.1 million!
200
Suppose the force exerted on an object stays constant. What would happen to the acceleration of the object if we increased its mass?
Acceleration would decrease.
200
What are we really measuring when we measure weigth?
The force of gravity acting on an object
200
If I push on the wall with a force of 20 N, what amount of force does the wall push back against me with?
20 N
300
Name the forces acting on this sky diver. Determine the Net Force.
Fgrav and Fair
Fnet = 39 N Down
300
According to the 1st Law, why is this object accelerating?
An unbalanced force acted upon it.
300
You are playing with a marble that has a mass of 0.5 Kg. You push it with a forward acceleration of 40 m/s2. How much force did you apply to the marble?
20 N
300
Your buddy has a mass of 45 Kg. What dies he weigh?
Oh and your buddy lives on venus which has a gravity that accelerates you at 8.87 m/s2.
399.15 N
300
Solve this 3rd Law problem.
Balloon surface pushes compressed air inwards.
400
Draw a FBD for a soccer ball rolling on grass. The ball is slowing down. Make sure to label ALL forces
400
You lost your favorite rock in space :(
It is traveling at 3 m/s into deep space. Will it ever slow down? Why or why not?
It will not ever slow down because there are no forces to act on it such as gravity or air resistance.
400
Your friend is about to get run over by a buffalo. You push them out of the way with a force of 50 N. They have a mass of 49 Kg. What was their acceleration?
1.02 m/s2
400
What is the weight of a car that has a mass of 4,500 Kg?
44,100 N
400
BONUS: What is the unit label for force?
What is the unit label for acceleration?
What is the unit label for weight?
Newtons (N)\
m/s/s or m/s2
Newtons (N)
500
What is the net force acting on this object? Is this object accelerating, or at a constant velocity?
Fnet = 5 N to the right
The object is accelerating because there is an unbalanced force acting on it.
500
Explain, using inertia, why it is harder to stop a moving car than a moving soccer ball.
A car has more mass which means more inertia which means more resistance to change.
500
Why was the blue plane able to accelerate at a higher rate than the red plane, even if the same force was applied?
Because the blue plane had less mass.
500
An African elephant can reach heights of 13 feet and possess a mass of as much as 6000 kg. Determine the weight of an African elephant.
58,800 N
500
What happens to the weight of a rocket as it moves further away from the Earth?
A - stays the same because mass stays the same
B - increases due to g-force
C - decreases due to mass increasing
D - decreases because gravity decreases
D