Balanced vs. Unbalanced Forces
Net Force
Newton's Laws
Force, Mass and Acceleration
Vocab
100
What does it mean when the forces are balanced?
The object is either traveling at a constant speed, or they are stopped.
There is no change in motion.
100
What is a Net Force?
The sum of the forces acting on an object.
100
What is Inertia?
The tendency of an object to resist change in motion. An object in motion will stay in motion until an unbalanced force acts upon it. An object at rest will stay at rest until an unbalanced force acts upon it.
100
Draw the math triangle for Force, Mass and Acceleration
100
What is a Force
A push or a pull
200
What causes an object to accelerate?
An unbalanced force.
200
A rope is being pulled on by two students. Student 1 pulls to the left with 100N and student 2 pulls to the right with 100N. What is the Net Force?
100N - 100N = 0N which means no movement.
200
An force of 10 Newtons is applied to a 5 kg car and a 10 kg car.... which one will accelerate more?
The 5 kg car, because it has less mass so it needs less force to accelerate.
200
How much force is needed to accelerate a 10 kg car 10m/s2?
10 kg x 10m/s2= 100 Newtons
200
What is a criteria
A minimum requirement or goal of a design.
300
What does it mean if the forces on an object are unbalanced?
The object will accelerate. Speed up, slow down or turn.
300
A block sits on a very smooth surface. Joey pushes it to the left with a force of 500 N. At the same time, Josh pushes it to the right with a force of 100 N. What is the net force?
500N - 100N = 400 N to the left
300
What is Newton's 3rd law?
For every action there is a reaction.
When objects interact they apply equal forces in opposite direction to each other.
300
How much force is needed to accelerate a 25 kg car to 5 m/s2?
25kg x 5 m/s2= 125 Newtons
300
What is a constraint
Something that limits the solution to a problem in a design
400
A person driving 20 miles per hour. Are the forces balanced or unbalanced?
Balanced. A constant speed.
400
Two students are pushing in the same direction on a huge box. Student 1 is pushing with a force of 200N and Student 2 is pushing with a force of 123N. What is the Net force?
200N + 123N = 323N
400
When a person sits in a chair explain what is happening using Newton's 3rd Law.
A person applies a force to the chair, while the chair applies an equal force in the opposite direction to the person.
400
With a force of 10 N the ball accelerates 2 m/s2, what is the mass of the ball?
10N / 2m/s2 = 5 kg
400
What is friction
a force that exists at the boundary between any two pieces of matter in contact with each other
500
A ball rolls across a smooth surface at a constant speed of 0.5 m/s. What is its acceleration?
The acceleration is zero.
They are moving at a constant speed. The forces are balanced, so there is no change in motion.
500
A student pushes to the right with a force of 100 N, another student pushes to the left with a force of 105 N, what is the direction of movement?
5 N to the left
500
Draw an explanation of Newton's 3rd law when a car hits a tree.
Example should show equal arrows in opposite direction
500
An object with a mass of 5 kg collides with an object with a mass of 4 kg. During the collision, the more massive object accelerates at a rate of 2 m/s2. What is the acceleration of the less massive object?
5 kg x 2m/s2= 10 N
10N / 4kg = 2.5 m/s2
500
What is acceleration
When an object speeds up, slows down or changes direction