Net Force
Word problems
Vocab
Potential & Kinetic Energy
More Net Force
100
What is the net force?
What direction will the dot go?
Are the forces balanced or unbalanced?
400N
to the LEFT
Unbalanced
100
Do you have to push against a box less than, greater than, or equal to the force of friction to get the box to start moving?
GREATER THAN the force of friction!
100
a push or pull
What is force?
100
Following the pink droplet of water from the sprinkler.....
Where does it have the most KINETIC energy?
Point E, right before it hits the ground!
100
What is the net force?
What direction will the dot go?
Are the forces balanced or unbalanced?
200N
to the RIGHT
UNBALANCED!
200
What is the net force?
What direction will the dot go?
Are the forces balanced or unbalanced?
0N
it will stay in the same place!
BALANCED!
200
A professional rollerblader is cruising along the boardwalk along a beach when they encounter a section of the boardwalk covered in sand. What will happen to their speed AND WHY?
Slow down because of friction
(the sand makes the boardwalk a rougher surface, so increases friction!)
200
the resistance of motion when one object rubs against another
what is friction?
200
Following the pink droplet of water from the sprinkler.....
Where does it have the most POTENTIAL energy AND WHY?
Point C because it's the highest
**Even though the water droplet is STILL MOVING, point C still has the most potential because of its height!
200
What is the net force?
What direction will the dot go?
Are the forces balanced or unbalanced?
250N
to the LEFT
UNBALANCED
300
What is the net force?
What direction will the rope go?
Are the forces balanced or unbalanced?
50N
to the LEFT
UNBALANCED
300
Define:
-Positive Acceleration
-Negative Acceleration
-Centripetal Acceleration
Positive Acceleration: speed up
Negative Acceleration: slow down
Centripetal Acceleration: moving in a circular path
300
How can I increase an object's gravitational potential energy?
Lift it higher
(the higher it is the more PE it has!)
300
The picture shows a cannonball's path after it was fired from a cannon. At which two points does the cannon have the EXACT SAME amount of potential energy?
Points B and D because they're the same height
300
A brother is pulling a toy from his sister with a force of 6 N. The sister is pulling back with a force of 8 N.
Who gets the toy?
What is the net force?
The sister gets the toy of course since she is pulling with a stronger force.
Net force = 8 N - 6 N
Net force = 2 N.
400
You and your brother are moving a car with a dead battery. You are pushing in a westward direction with a force of 20 N and your brother is pushing westward with a force of 25 N. What is the net force AND direction of the car?
Since you are pushing the car in the same direction, the forces will be added together.
Net force = 45 N
The car is moving WEST (or in a westward direction)
400
Jeremy is riding his bike at a constant speed of 12 miles per hour. He makes a right-hand turn and continues at the same speed. What changed?
his ACCELERATION!
Acceleration is a change in speed (speed up or slow down) OR a change in direction!!
**So it can meaning speeding up, slowing down, OR JUST CHANGING DIRECTION!
400
Speed is a determinant for what type of energy?
Kinetic Energy
400
The picture shows three different swingers on the swing set. If each of them was to fall right at this moment, which one would hurt the most AND WHY?
Swinger 1 because they have the most potential energy! (When they fall, they will gain the most speed/kinetic energy before hitting the ground!)
400
Which force would need to increase to slow down the parachuter's descent (fall)?
Air resistance
500
4 people are playing tug of war. Two are pulling on the right side. Two are pulling on the left side. On the right side, one is pulling with a force of 60 N and the other with a force of 70 N. On the left side, one is pulling with a force of 30 N. How much force should the second person on the left apply to keep the net force balanced?
The net force is balanced if the net force is 0.
The forces on the right is equal to 60 N + 70 N = 130 N
30 N + WHAT = 130 N
The other person should pull with a force of 100 N to keep the rope balanced!
500
What are the two things that will DECREASE friction (and speed you up!)?
1. smoother surfaces
2. less weight/force pressing the 2 surfaces together
500
What is responsible for a change in acceleration? (speeding something up, slowing it down, or changing its direction)
UNBALANCED FORCES!
500
The total amount of energy in the ball as it drops is 100 J. At point C there is only 24 J of potential energy. How many J of kinetic energy is there?
76 J
500
What is the net force?
What direction will the wagon go?
Are the forces balanced or unbalanced?
15 N
to the Right
UNBALANCED!