A force is a **push or pull** exerted by one object on another.
2. What unit is force measured in?
Force is measured in **newtons (N)**.
3. List three effects that a force can have on an object.
A force can change an object's **speed**, **direction**, or **shape**.
4. What is friction?
Friction is a **force that opposes motion** between surfaces in contact.
5. Name two types of friction.
Two types of friction are **static friction** and **dynamic friction**.
6. What is air resistance?
Air resistance is a type of **friction** that acts on objects moving through the air.
7. State Newton’s first law of motion.
An object stays at rest or continues to move in a straight line at a constant speed unless acted upon by a **resultant force**.
8. What is the formula relating force, mass, and acceleration?
**Force = mass × acceleration** or **F = ma**.
9. What is a resultant force?
A resultant force is the **single force that has the same effect** as two or more forces acting on a body.
10. What is the relationship between the extension of a spring and the force applied to it, according to Hooke’s Law?
The extension of a spring is **proportional to the load applied**, provided the limit of proportionality is not exceeded.
11. Explain how friction can be both helpful and a hindrance.
Friction is helpful because it allows us to **walk** and is used in **braking systems**. It is a hindrance because it **slows down moving parts** in machinery and produces heat, which wastes energy.
12. Describe how to determine the resultant force when multiple forces act on an object in the same or opposite directions.
When forces act in the **same direction, add them together**. When forces act in **opposite directions, subtract the smaller force from the larger force**, and the resultant force acts in the direction of the larger force.
13. Explain Newton’s first law of motion and provide an example.
Newton's first law states that an object will remain at rest or continue moving at a constant velocity unless acted upon by a resultant force. For example, a book on a table will stay at rest unless someone picks it up or pushes it.
14. Explain how air resistance affects a falling object.
Air resistance is a form of friction that opposes the motion of an object through the air. As an object falls, air resistance **increases with speed**, reducing the object's acceleration. Eventually, the air resistance may equal the object's weight, resulting in a constant terminal velocity.
15. Explain how the design of an aircraft considers different forces during various stages of flight.
When designing an aircraft, engineers consider forces such as thrust, air resistance, weight, and lift. During **take-off**, thrust must overcome air resistance and weight for acceleration. In **level flight**, lift equals weight, and thrust equals air resistance to maintain a constant speed. During **landing**, air resistance and braking forces are used to decelerate the aircraft.
Explanation Questions
Explain how friction can be both helpful and a hindrance.
Friction is helpful because it allows us to walk and is used in braking systems. It is a hindrance because it slows down moving parts in machinery and produces heat, which wastes energy.
Describe how to determine the resultant force when multiple forces act on an object in the same or opposite directions.
When forces act in the same direction, add them together. When forces act in opposite directions, subtract the smaller force from the larger force, and the resultant force acts in the direction of the larger force.
Explain Newton’s first law of motion and provide an example.
Newton's first law states that an object will remain at rest or continue moving at a constant velocity unless acted upon by a resultant force. For example, a book on a table will stay at rest unless someone picks it up or pushes it.
Explain how air resistance affects a falling object.
Air resistance is a form of friction that opposes the motion of an object through the air. As an object falls, air resistance increases with speed, reducing the object's acceleration. Eventually, the air resistance may equal the object's weight, resulting in a constant terminal velocity.
Explain how the design of an aircraft considers different forces during various stages of flight.
When designing an aircraft, engineers consider forces such as thrust, air resistance, weight, and lift. During take-off, thrust must overcome air resistance and weight for acceleration. In level flight, lift equals weight, and thrust equals air resistance to maintain a constant speed. During landing, air resistance and braking forces are used to decelerate the aircraft.