Mechanics Flashcards
What is newton’s first law?
The law states that an object stationary or in motion will continue to unless an external force is acts on it
What is Newton’s second law?
Newton’s second law states that the acceleration of an object is dependant on two variables: Net force and mass of the object.
What is Newton’s third law?
Any force on the object has an equal but opposite force acting upon it. (Interactive pairs!)
What is the equation for momentum?
Momentum = Mass x Velocity
What are the units for Momentum?
there are 2
Ns kgms-1
What are the 7 base quantities?
Mass Length Time Current Temperature Amount of substance Luminous intensity
What’s the difference between scalar and vector quantities?
Scalar has a magnitude
Vector has a magnitude and a direction
What equation do you use to find the resultant force of a right angle triangle?
A + B = C
squared
What two equations can you use to find a final vector with 2 or more given to you
Pythagoras
trigonometry
What is the rotational equilibrium state?
The sum of the clockwise forces are equal to the sum of anticlockwise forces acting on an object if it’s in equilibrium.
What is a moment?
The turning effect of a force
What does the moment on a rotational force depend on?
The size of the force and the size of the perpendicular distance between the force line and axis of rotation.
In projectiles, what will the vertical motion always be?
Accelerating at 9.81
Calculate the average force needed to change the momentum of a body from 3.2Ns to 4.8Ns in 50 seconds
F= change in momentum/ Time F= 1.6/0.5 = 3.2N
In the principle of moments, why would the object not be accelerating
If forces are balanced the object can’t accelerate.
What are couples?
Where two forces are applied to an object
What is torque?
The overall turning effect of couples
What is the equation for moment of a force?
Force x perpendicular distance from the pivot
What is the equation to find t from s=ut+0.5axtsquared?
T=square root 2xU over a
What is the conservation of momentum?
The total momentum before has to be equal to the total momentum afterwards
What is the gradient of the line in a displacement time graph?
The velocity = CID/CIT
What is the gradient of the line in a velocity time graph?
The acceleration
