1.2 Dynamics Flashcards
Give a few examples of forces…
Weight, friction, thrust, lift, magnetic
What does force change?
Speed, direction and shape of an object.
What is used to measure force?
A newton balance. 1N = 1cm extension
What is weight?
The Earth’s pull on an object.
Is weight a scalar or vector quantity?
vector
What are the symbol and unit for weight?
W and newtons (N)
What is the equation for weight?
W=mg
weight equal mass times gravitational field strength
What is mass?
The measure of matter within an object.
Is mass a scalar or vector quantity?
scalar
What are the unit and symbol for mass?
m and kilograms (kg)
What is gravitational field strength?
The weight per unit mass.
What are the symbol and unit of gravitational field strength?
g and newtons per kilogram (N/kg)
What is the value of gravitational field strength on Earth?
10N/kg
What is the force of friction?
Opposes the motion of the object.
In what situations is friction wanted?
sitting, driving, writing, bikes, walking
In what situations is friction unwanted?
racing cars, fast cars
What can be done to reduce friction?
lubrication, streamlining, ball bearings
What is Newton’s 1st Law of Motion?
An object will continue to travel at a constant velocity unless acted on by an unbalanced force.
What are balanced forces?
Forces that are opposite in direction but equal in magnitude.
Is force a vector or scalar quantity?
vector
What is Newton’s 2nd Law of Motion?
Acceleration of an object is directly proportional to the magnitude of unbalanced force acting and inversely proportional to the mass.
What is the equation linking force, mass and acceleration?
F=ma
force (F) equals mass (m) times acceleration (a)
What is the newton and it’s symbol?
The force needed to accelerate 1kg at 1m/s. (N)
What is the resultant force?
The resulting force acting on an object when balanced forces have been subtracted.
What is the method of calculating resultant force? (3 steps)
1) free body diagram 2) tip to tail 3) calculate resultant
Explain the equivalence of acceleration due to gravity and gravitational field strength…
F=W F=ma W=mg
ma=mg
a=g
Which objects does acceleration due to gravity affect and what is its symbol?
objects in freefall accelerate at a rate equal to the acceleration due to gravity. (a)
What is a projectile?
An object traveling horizontally and vertically at the same time.
Explain the curved path of projectiles in terms of the force of gravity…
Vertically the object accelerates due to gravity and the combined result of horizontal and vertical motion is a curved path.
