Unit 1 APPLICATION OF FORCES AND TRANSFER OF ENERGY Flashcards
SI unit for Force:
Newton (N)
Apparatus to measure Force
- Spring Balance
- Dynamometer
In what ways are Friction advantageous?
- Improved grip
- Prevents slipping
- Writing
- Slowing down or stopping objects
- Moving on muddy or wet surfaces
- Door stoppers
Types of Forces:
- Magnetic Force
- Elastic Force
- Frictional Force
Definition of Elastic Force:
- Elastic Force is a contact force that comes into play when an object is stretched or compressed from its original shape.
Definition of Gravitational Force:
- As long as objects possess mass, they can exert an attractive force on each other.
Can exert force when Pushed or Pulled (from its original form)
Elastic Force
Definition of Gravitational Field Strength:
It tells us the amount of gravitational force it exerts on every 1 kg of mass.
SI unit of time
second (s)
Relationship between mass of an object and its gravitational field strength
The greater the mass of the object, the stronger its gravitational field strength
SI unit of mass
kilogram (kg)
SI unit of electric current
ampere (A)
SI unit of time
meter (m)
How is gravitational field strength expressed?
N/kg (denoted as “g”)
SI unit of temperature
kelvin (K)
Characteristics of a Significant Gravitational Force:
- The force is strong enough to move or affect the objects involved.
- One or both objects typically have a substantial mass
Define the effect of forces:
When two or more objects interact, they can exert forces on each other, leading to a possible transfer of energy between them and observable changes in these objects.
Weight is referred to as..
The total amount of gravitational force acting on an object of any mass.
Definition of mass
The amount of matter in an object
Definition
W = m x g
kg x N/kg (g) = N
Definition of magnetic force
It is a force exerted between magnets or between a magnet and magnetic substances.
Characteristics of Mass:
- The mass remains unchanged in different locations
- SI unit: Kilogram (kg)
- Measuring instrument: Beam balance, electronic balance
Characteristics of Weight:
- The weight of the object varies in different locations
- SI unit: Newton (N)
- Measuring instrument: Spring Balance, Dynamometer
Definition of Moment of a Force
It is a measure of the turning effect of a force applied to a point on an object
What is pressure defined by
Force per Unit Area
M = F × d
Moment (Nm) = Force (N) × DistancefromPivot (m)
W = m × g
Weight N() = mass (kg) x gravitational field strength (N/kg)
W = F x s
Work done (J) = Force (N) x Distance (m)
Why do we feel Cold and face Low Surrounding Pressure when at a high up place compared to a place lower on the ground.
The higher you go, the less air there is in the atmosphere hence there is less air mass pressing you down. (Gravity pulling air particles down typically).
The cold is due to thinner air’s reduced ability to retain heat, and the low pressure affects your body as it adapts to the changes in oxygen levels and the overall environment.
Conditions for Work NOT to be considered done (2 Ways)
- The object does not move even when a Force is applied
- The direction of motion of the object is not the same as the applied force.
Why is it harder to push the same mass object up-hill compared to on flat ground?
- Up-hill: You are working against BOTH Friction and Gravity acting on the object
- On flat ground: The force you apply only needs to overcome the friction acting on the object.
How does an increase in energy occur?
- Transferring energy
- Converting energy
What is the law of conservation of energy?
Energy cannot be created nor destroyed
What are Sources of Energy?
Energy sources refer to various natural phenomena (sunlight) or natural processes (fossil fuels) from which energy stored in them can be harnessed and converted to usable forms.
Examples of non-renewable energy sources (2 types)
- Fossil Fuels (takes very long to form -> millions of years)
- Nuclear (composed with finite resources -> Uranium)
