Forces Flashcards
(73 cards)
Define mass and weight.
Mass- Amount of matter in an object.
Weight- The force with which the earth attracts a body towards its centre.
Give the formula for weight.
W= mg
Explain equilibrium.
When weight= resultant force and net force= 0.
Define inertia.
The tendency of an object to continue in its state of rest unless an external force is applied.
What’s momentum and the law of conservation of momentum?
The total momentum before and after the collision remain the same.
Give the formula for stopping distances.
Stopping distance= Thinking distance (0.2-0.9)+ braking distance
Explain the difference between distance and displacement.
Distance- Path between two points. (scalar)
Displacement- Shortest path between two points. (vector)
Define scalar and vectors.
Scalar- Quantity w/ magnitude.
Velocity- Quantity w/ magnitude + direction.
Define force.
A push/pull that acts on an object due to interaction with another object.
What can forces affect?
Shape, speed and direction
Describe the forces: weight, electrostatic, thrust and reaction force.
Weight- force of gravity on mass.
Electrostatic- Force between unlike charges.
Thrust- Any force causing an object to move.
Reaction force- A force due to contact between objects, force pairs.
Describe the forces:
air resistance, upthrust, compression and tension.
Air resistance- friction of air on moving object.
Upthrust- fluid pushing an object up to make it float
Compression- Force squeezing an object inwards.
Tension- Wire pulled by opposite ends.
What’s the difference between contact and non-contact forces.
Contact- forces between objects physically touching
Non-contact- forces acting at a distance.
Are forces scalar or vector quantities?
Vector they have magnitude (N) and direction (up/down/in angles)
What is a force pair and which of Newtons laws does it relate to?
Force pair- Interaction between two objects and a force is exerted on each object.. 3rd law: every action has an equal and opposite reaction.
What are the two method of measuring weight?
1- Find mass of object using a balance, then calculate.
2- Use a newton meter connected to a spring to hold the object.
Where is the center of mass?
Located at the point of symmetry, or at balance point. The point where the weight of the object acts.
How fast will a free falling object accelerate at towards the earth?
9.81 m/s^2
What’s a resultant force?
A single combined force that describes the action of all forces acting on an object. (determines magnitude and direction)
What are balanced and unbalanced forces?
Balanced- Forces cancel each other out, no resultant force.
Unbalanced- Forces combine, one force is greater than the others, this is the resultant force.
What are examples of forces acting on isolated systems?
Tension: force on rope when pulled.
Normal contact force: force that acts as object rests perpendicular.
Upthrust: upwards buoyancy on an object in a fluid.
Friction: Force when two surfaces are in contact.
What do resolving force diagrams represent?
If a force is acting at an angle, it can be broken down into two (horizontal and vertical)
What is work done?
Energy transferred when a force moves an object over a distance.
What is the formula for work done?
Force (N) x Distance (m)