18 Questions
What type of force causes a change in motion?
Unbalanced force
How is the net force calculated when unbalanced forces act in opposite directions?
By subtracting the forces
When combining forces, what happens if all the forces are pointed in the same direction?
They add together
What does a negative acceleration indicate when forces are unequal and acting in opposite directions?
Negative acceleration
How does combining forces affect an object's motion?
Causes a change in speed and/or direction
What happens when multiple forces are not equal and act in opposite directions?
They subtract from each other
Which of the following statements about forces is true?
A force is anything that causes an object to accelerate.
What is the SI unit for measuring force?
Newton (N)
When two forces act in the same direction, how is the net force determined?
The net force is the sum of the two forces.
If a force of 10 N acts on an object in the north direction and another force of 7 N acts on the object in the south direction, what is the net force on the object?
3 N in the north direction
How can the net force be determined when two forces act at right angles to each other?
Use the Pythagorean theorem to find the resultant force.
What instrument is typically used to measure forces?
Spring scale
What formula is used to calculate the resultant force of two forces at right angles?
a² + b² = c²
In balanced forces, what is the net force?
Zero
What happens when multiple forces are balanced out?
No movement happens
If two football players push on each other equally hard, what happens according to balanced forces?
Neither player moves
What occurs when forces are unbalanced?
Movement in one direction
How do balanced forces affect the motion of an object?
Prevent any change in motion
Study Notes
Unbalanced Forces
- An unbalanced force always causes a change in motion because the net force is greater than 0.
- When unbalanced forces act in opposite directions, the net force can be found by subtracting the smaller force from the larger force.
- The direction of the net force is the direction of the larger force.
Combining Forces
- When multiple forces act in the same direction, they add together to determine the net force.
- When multiple forces act in opposite directions, they subtract from each other to determine the net force.
- Forces can be combined using the Pythagorean Theorem (a2 + b2 = c2) when adding only 2 vectors that make a right angle.
Force Measurement and Units
- The SI unit for force is the Newton (N).
- 1 N is a force that causes a 1kg mass to accelerate at a rate of 1m/s/s.
- Forces are measured using a spring scale.
Forces in Pairs
- Forces come in pairs and have a magnitude and a direction.
- Force is a vector quantity, e.g. 5N, north (up).
Balanced and Unbalanced Forces
- Balanced forces are equal in size and opposite in direction, resulting in a net force of 0.
- Balanced forces do not cause a change in motion.
- Unbalanced forces are not equal in size and can cause acceleration on an object.
Examples of Forces
- A person pushing a car is an example of an unbalanced force.
- Multiple people pushing a car together is an example of multiple forces combining to move an object.
- Gravity pulling down on an object and the ground pushing back up is an example of balanced forces.
Learn about the concept of force in physics, including its definition, characteristics, and effects on the motion of objects. Understand the difference between balanced and unbalanced forces, as well as how to calculate the net force acting on an object.
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