Mechanics Flashcards
Questions which you've gotten wrong because you aren't thinking (20 cards)
The mass of an astronaut on Earth is M.
At a heigh equal to twice the radius of the Earth, above the surface of the earth, the mass of the astronaut will be…
M
Which of the following best describes the effect of a resultant force on an object?
A- If the object is moving at constant velocity, there is a constant resultant force acting on it.
B- The change in acceleration of the object is equal to the resultant force acting on it.
C- The rate of the change of velocity of the object is directly proportional to the resultant force acting on it.
D- The mass of the object changes in direct proportion to the resultant force acting on it.
C
An object is moving at constant velocity. What is the net resultant force being applied to it?
0N
How do you calculate acceleration without the use of the equations of motion?
With Gradient
∆V\ ∆t
Object accelerating to the left.
√√√√√√√√√√√√√
∆v = 20
∆t = 10
What is the acceleration of this object?
2m/s/s to the left.
How do you calculate the displacement from a velocity time graph?
Calculate area underneath the graph
∆x = area under the graph
What does the acceleration
2m/s/s
look like on an acceleration time graph?
(And equation of line)
A straight line at 2
Equation is
Y= 2
Define Velocity
Rate of change of displacement per unit time.
Frictional Force definition
Frictional force is the source that opposes the motion of an object and acts parallel to the surface which is in contact with the object.
What does it mean if something is in equilibrium?
The net resultant of all forces acting the object is 0
What is a resultant force?
A force equal to the sum of all forces acting on an object.
State Newton’s first law of motion
A body will remain at in its state of rest or motion at constant velocity
UNLESS
a non-zero resultant/net force acts upon it.
What is inertia?
Resistance of ant physical object to any change in velocity.
State Newton’s Second law of Motion
When a resultant force acts on an object, it will accelerate in the direction of the force
at an acceleration which is directly proportional to the force applied and inversely proportional to the mass of the object.
State Newton’s 3rd Law
If object A exerts a force on object B,
object B exerts an equal but opposite force on object A.
What do you do ALWAYS before attempting a tension question?
Write down the DIRECTIONS of ALL the forces you see.
A bus is driving along a straight section of road, with a soccer resting on the floor next to a passenger. At some point they notice that the ball starts rolling to the front of the bus.
With reference to Newton’s first law, explain whether the bus driver had applied the brakes or the accelerator?
(3 marks)
The ball will want to remain at content velocity.
The ball appears to roll forward and must be moving faster than the bus.
This we can conclude that the bus has allowed down and that the driver has applied the brakes.
Total Distance Vs Total displacement
Just remember the difference.
NBNBNBNBNBNBNBNBNBNBNB
Principle of Conservation of Mechanical Energy
In the absence of air resistance or any external force, the mechanical energy of an object is constant.
State Newton’s Law of Gravitational Acceleration.
Ever particle in the universe attracts every other particle in the universe with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres.
