Chapter 3: Forces Flashcards
What is Newton’s first law?
Newton’s first law states that every object will continue in its state of rest or uniform motion in a straight line unless a resultant force acts on it.
What is Newton’s second law?
Newton’s second law of Motion states that when a resultant force acts on an object of a constant mass, the object will accelerate in the direction of the resultant force. The product of the mass and acceleration of the object gives the resultant force.
What is Newton’s third law?
Newton’s third law of motion states that for every action, there is an equal and opposite reaction.
What is a force?
A force is an action which changes the shape, size, state of rest, or motion of a body. It can either be a push or pull.
(a) State an instrument to measure the magnitude of a force
(b) State the SI unit of force
(c) Define “one newton”
(a) Spring balance
(b) Newton(N)
(c) One Newton is defined as the force which produces an acceleration of 1m/s2 when it acts on a mass of 1kg
What is friction?
Friction is the contact force that opposes or tends to oppose motion between surfaces in contact.
Using newton’s third law, explain how a swimmer is able to move forward by kicking the wall of the swimming pool
Third law states that there is an equal and opposite reaction to every action, thus when the swimmer exerts a push force on the wall, the wall in return exerts a push force of equal magnitude on the swimmer, causing him to move forward.
What are 2 ways to find net force acting on an object?
- Force = mass x acceleration
2. Net force = force applied - frictional force
What are 4 forces acting on an object flying in the air?
- Drag
- thrust
- Lift
- Weight/gravitational force
How is friction beneficial and harmful to us
Friction is beneficial as it:
- Allows us to run and walk
- Allows us to pick up objects
Friction is harmful as it:
- Causes an object to wear and tear
- Generates heat as waste energy in machinery
