Forces Web Search Notes 2.28.12
Use the following websites to build your notes on forces:
http://www.engineeringinteract.org/resources/parkworldplot/flash/concepts/balancedandun.htm
http://www.bbc.co.uk/schools/ks3bitesize/science/energy_electricity_forces/forces/revise6.shtml
http://www.mansfieldct.org/schools/mms/staff/hand/lawsunbalancedforce.htm
1. What must occur for an object to accelerate?
It must be acted upon by an outside object for the velocity to change.
2. A net force is the sum of all forces acting upon an object.
Read the scenario and answer the questions that follow:
Two forces are acting upon an object in opposite directions. One force is 80N and the other force is 35N.
3. Are the forces balanced or unbalanced? Explain your answer.
Unbalanced, because there is a net force greater than zero.
4. Calculate the net force on the object.
The net force is 80-35=45 N.
5. When velocity is constant there is no net force nor unbalanced force.
6. Define what a Resultant force is and give an example.
It is the overall force acting on an object. Example: 100-60=40.
7. Speed and direction change when the forces are unbalanced. (velocity)
8. One of the websites provides an example of a large truck being acted upon by two opposing forces. Explain why the truck will move in the direction of the 100N force.
Because the force is larger than the other side, so it will move in that direction.
9. True or False. When a force is named as 70N, the N means “North.” If the statement is false correct
the statement.
False. The N stands for Newtons.
10. Describe an object with a balanced force.
A book on a flat table, because it is not moving and there is no net force.
11. Describe an object with an unbalanced force.
If there is a group playing tug of war, then the force will be unbalanced.
Explore the various rides using the website: http://www.learner.org/interactives/parkphysics/index.html
13. Give an example of unbalanced forces, make sure and explain why you believe it is an unbalanced
force.
A game of tug of war when one team loses because they are going in a direction they were not originally going.
14. Give an example of a negative net force make sure and explain why you believe it is a negative net
force.
A car driving left, because net forces going left are negative.
15. Give an example of a positive net force, make sure and explain why you believe it is a positive net
force.
A car driving right, because net forces going right are positive.
16. Describe an object with an unbalanced force, make sure and explain why you believe it is an
unbalanced force.
A boat in the water, because the boat is moving and it will have a net force.
17. Describe an object with a balanced force, make sure and explain why you believe it is a balanced force.
A book on a flat surface, because it is not moving, so there is no net force and it is not accelerating.
http://www.engineeringinteract.org/resources/parkworldplot/flash/concepts/balancedandun.htm
http://www.bbc.co.uk/schools/ks3bitesize/science/energy_electricity_forces/forces/revise6.shtml
http://www.mansfieldct.org/schools/mms/staff/hand/lawsunbalancedforce.htm
1. What must occur for an object to accelerate?
It must be acted upon by an outside object for the velocity to change.
2. A net force is the sum of all forces acting upon an object.
Read the scenario and answer the questions that follow:
Two forces are acting upon an object in opposite directions. One force is 80N and the other force is 35N.
3. Are the forces balanced or unbalanced? Explain your answer.
Unbalanced, because there is a net force greater than zero.
4. Calculate the net force on the object.
The net force is 80-35=45 N.
5. When velocity is constant there is no net force nor unbalanced force.
6. Define what a Resultant force is and give an example.
It is the overall force acting on an object. Example: 100-60=40.
7. Speed and direction change when the forces are unbalanced. (velocity)
8. One of the websites provides an example of a large truck being acted upon by two opposing forces. Explain why the truck will move in the direction of the 100N force.
Because the force is larger than the other side, so it will move in that direction.
9. True or False. When a force is named as 70N, the N means “North.” If the statement is false correct
the statement.
False. The N stands for Newtons.
10. Describe an object with a balanced force.
A book on a flat table, because it is not moving and there is no net force.
11. Describe an object with an unbalanced force.
If there is a group playing tug of war, then the force will be unbalanced.
Explore the various rides using the website: http://www.learner.org/interactives/parkphysics/index.html
13. Give an example of unbalanced forces, make sure and explain why you believe it is an unbalanced
force.
A game of tug of war when one team loses because they are going in a direction they were not originally going.
14. Give an example of a negative net force make sure and explain why you believe it is a negative net
force.
A car driving left, because net forces going left are negative.
15. Give an example of a positive net force, make sure and explain why you believe it is a positive net
force.
A car driving right, because net forces going right are positive.
16. Describe an object with an unbalanced force, make sure and explain why you believe it is an
unbalanced force.
A boat in the water, because the boat is moving and it will have a net force.
17. Describe an object with a balanced force, make sure and explain why you believe it is a balanced force.
A book on a flat surface, because it is not moving, so there is no net force and it is not accelerating.
A force is a push or a pull that is capable of changing the velocity of a mass. Forces are measured in “Newtons” or “N”, in honor of Sir Isaac Newton. According to Mr. Newton, an object will only accelerate if there is “net force” acting upon it. A net force is the sum of all forces acting on an object. A net force is capable of accelerating a mass. For instance, if the wheels of a car push it forward with 5 Newtons and drag is 3 Newtons, the net force is 2 Newtons, forward. Motion to the right is positive. Motion to the left is negative.
If an object has a net force acting on it, it will accelerate. The object will speed up, slow down or change direction. An unbalanced force (net force) acting on an object changes its speed and/or direction of motion. An unbalanced force is an unopposed force that causes a change in motion. A net force = unbalanced force. If however, the forces are balanced (in equilibrium) and there is no net force, the object will not accelerate and the velocity will remain constant.
If the forces on an object are unbalanced this is what happens:
If an object has a net force acting on it, it will accelerate. The object will speed up, slow down or change direction. An unbalanced force (net force) acting on an object changes its speed and/or direction of motion. An unbalanced force is an unopposed force that causes a change in motion. A net force = unbalanced force. If however, the forces are balanced (in equilibrium) and there is no net force, the object will not accelerate and the velocity will remain constant.
If the forces on an object are unbalanced this is what happens:
- an object that is not moving starts to move
- an object that is moving changes speed or direction
Net Force example: What is the net force if the wheels of the car apply 10 Newtons but a parachute applies 7 Newtons in the other direction?
The net force would equal 3 Newtons, forward. The mass will accelerate.
The net force would equal 3 Newtons, forward. The mass will accelerate.
Resultant forces
The size of the overall force acting on an object is called the resultant force. If the forces are balanced, this is zero.
The size of the overall force acting on an object is called the resultant force. If the forces are balanced, this is zero.
Balanced Forces: When forces are in balance, acceleration is zero. Velocity is constant and there is no net or unbalanced force. A plane will fly at constant velocity if the acceleration is zero.