Balanced/Unbalanced Forces
Newton's 1st Law
F=m * a
Newton's 2nd Law
Newton's 3rd Law
100
Explain what happens to an object’s motion when forces are balanced. Use proper terminology.
The object stays at rest or moves at a constant speed.
100
Why does a passenger in a car continue moving forward when the car suddenly stops? Use proper terminology.
Inertia causes the body to resist change in motion. The person's body continues to move until it meets and unbalanced force.
100
If a 30 N force causes an object to accelerate at 3 m/s², what is the object’s mass?
m=f/a, force=30N acceleration = 3m/s2 m=30N / 3m/s2 mass=10kg
100
Provide an example of Newton's Second Law.
Pushing a car; the more force you apply, the faster it accelerates. a=f/m e.g. a= 700N/1,000kg = .7 m/s2 a= 1200N/1,000kg = 1.2 m/s2
100
A swimmer pushes the water backward with her hands. What direction will the swimmer move?
The swimmer moves forward.
200
What is the net force?
0 Newtons
200
What is Newton's First Law?
An object at rest stays at rest, and an object in motion stays in motion unless acted upon by an unbalanced force.
200
What is the formula to find force?
Force = mass * acceleration
200
A soccer ball has a mass of 0.25 kg and accelerates at 8 m/s². What is the net force acting on the ball?
f=m*a, mass=.25kg, acceleration=8m/s2 f=.25kg * 8m/s2
f=2N
200
Identify the action and reaction forces when a bird perches on a fence post.
Action: Gravity and the bird pushes down; Reaction: Post pushes up on bird
300
How will this object move?
20N to the right
300
Describe a real to life situation in which an object remains at rest because the forces are balanced.
e.g. A book resting on a table has gravity and normal forces balanced.
300
A 4 kg cart experiences a 20 N net force. Describe the motion of the cart and calculate its acceleration.
It accelerates at 5 m/s²
300
You and your dad are moving the couch from one side to another. Your dad pushes with a force of 35 N to the right and you push with a force of 25 N right. What is the net force on the couch?
60 N right
300
Two rockets have the same mass, but Rocket A has twice the force applied. Which will have greater acceleration?
Rocket A
400
What is unbalanced force?
Forces that are not equal and cause a change in motion.
400
Explain what happens to an object when forces are unbalanced.
The object moves or has a change in motion.
400
If a cart has a mass of 100 kg and a force of 200 N, what is its acceleration? Provide your answer in meters per second squared (m/s2)
f=m*a then a=f/m force=200N, mass=100kg a=200N/100kg
a=2m/s2
400
A 6kg box is pushed with a force of 30N. What is the acceleration? Provide your answer in m/s2
a=f/m, force=30N, mass=6kg a=30N/6kg
a= 5m/s2
400
When you jump forward off a skateboard into the grass, the skateboard moves backward. Why?
Because you push on the skateboard and the Skateboard pushes back on you.
500
Define balanced forces.
Forces that are equal in size and opposite in direction, resulting in no change in motion.
500
What unit is force measured in?
Newtons
500
a 5kg bowling ball falls off the kitchen table, what is the force on impact.
f= m*a, mass=5kg acceleration= 9.8m/s2 f=5kg * 9.8m/s2 f= 49 N
500
A rocket has a mass of 5,000kg and engines with 120,000N of thrust. What is the rocket's acceleration at takeoff? Your answer must be in m/s2
a=f/m, force=120,000N, mass=5,000kg
a=120,000N / 5,000kg
a=24m/s2
500
What does Newton's Third Law state?
For every action, there is an equal and opposite reaction.