Forces Flashcards
What is a force?
A push or a pull that acts on an object due to the interaction with another object
Are forces scalar or vector quantities?
Vector
All forces have m____ and d____
magnitude and direction
What is the unit of forces?
Newton, N
What is a contact force?
A force that acts when the two objects are physically touching
Give two examples of a contact force
- Tension
- Friction
- Air Resistance
- Normal Contact Force
What is a non contact force?
A force that acts when the two objects are physically separated
Give an example of a non contact force
- Gravity
- Electrostatic Force
- Magnetism
What is meant by a Vector Quantity?
A quantity with magnitude and direction
Give two examples of vector quantities
- Velocity
- Force
- Displacement
- Acceleration
What is meant by a scalar quanity?
A quantity with only magnitude
Give two examples of scalar quantities
- Speed
- Distance
- Mass
- Temperature
- Time
What is the definition of mass?
The measure of how much matter is in an object
What is mass?
The measure of how much matter is in an object
What is the unit of mass?
Kg
What is weight?
The force acting in an object due to gravity
What is the equation for weight?
weight = mass x gravitational field strength
Describe the relationship between the weight and mass of an object
The weight of an object is directly proportional to its mass
What is the centre of mass of an object?
The point at which an object will balance because the weight on either side of the point is the same
What is meant by resultant force?
A single force that has the same effect as all the original forces acting together
What is meant by work done?
Energy transferred to or from an object which allows it to be moved
What is the equation for work done?
Work Done = Force * Distance
What can all forces be resolved into?
Two perpendicular components
When calculating the work done against gravity, why do you use the vertical distance?
Because the distance must be in the line of action of the force, and weight acts vertically downwards
What is meant by an elastic material?
One that will return to its original shape after being stretched, providing you haven’t exceeded its elastic limit
What happens to objects that have been elastically deformed after forces stretching them are removed?
They return to their original shape
What happens to objects that have been plastically deformed after forces stretching them are removed?
They don’t return to their original shape
Can you elastically deform an object with only one force? Why/Why not?
No, the object would move rather than change shape
What is the equation for the force required to stretch an elastic object
Force = spring constant * extension
Independent variable in the stretching a spring practical
The weight on the spring
Dependent variable in the stretching a spring practical
The extension produced by different weights
Control variable in the stretching a spring practical
Material of the spring
What is meant by elastic limit?
The greatest stress that can be applied without causing plastic deformation
What is the equation for elastic potential energy?
EPE = 1/2ke^2
What does a curve mean on a distance time graph?
A changing velocity
What is meant by acceleration?
The change in velocity per second
How can you find the distance travelled on a velocity time graph?
Calculate the area under the curve
What is Newton’s First Law?
An object will remain at rest or a constant velocity unless acted on by a resultant force
What is Newton’s second law?
The force acting on an object is proportional to the rate of change of momentum it causes
What is Newton III?
If object A exerts a force of object B, object B exerts an equal and opposite force on object A
Which two components make up stopping distance?
Thinking Distance and Braking Distance
What can affect the thinking distance?
• Blood Alcohol Level
• Tiredness
• Speed of the Car
• Drugs in the driver’s body
What can affect the Braking Distance?
• Weather
• Condition of the brakes
• Condition of tyres
• Mass of the car
Whats the equation for momentum?
Momentum = mass x velocity
What is meant by momentum?
It is a measure of how difficult it is to stop a moving object
Is momentum scalar or vector?
Vector
What does the conservation of momentum state?
In any collision the total momentum is constant in the absence of external forces
What is meant by an inelastic collision?
One where the total kinetic energy reduces due to being lost by heat or sound
What is an elastic collision?
One where the total kinetic energy before is the same as after
What is the equation for moments?
Force x Perpendicular Distance
What is a moment?
The turning effect of a force
What are levers and gears?
Force multipliers
