mechanics formula Flashcards
work done
force x distance
average power
work done / time taken
power incl velocity
force x velocity
momentum
mass x velocity
what is impulse?
force x time
what is impulse in relation to momentum?
change in momentum
what is the impulse generated by a variable force acting from time t1 to t2?
integral between t1 and t2 of the function of force
what is the coefficient of restitution?
relative velocity of separation (final velocity) / relative velocity of approach (initial velocity)
what is e in a perfectly elastic collision?
1
what is e if the spheres coalesce?
0
what is the linear speed of a partical on a horizontal circular path?
radius x angular speed
what is the acceleration of a particle on a horizontal circular path?
velocity squared / radius
what is the work done by a variable force acting from time x1 to x2?
integral between x1 and x2 of the function of force
what is the tension in a spring using spring const?
k x extension
what is the tension in a spring using the modulus of elasticity?
(modulus x extension) / natural length
what is work done against elasticity using spring const?
1/2 x k x extension squared
what is work done against elasticity using modulus?
(mod x extension^2) / 2 x natural length
what is the impulse of a variable force acting between t1 and t2?
integral of the function of the force between t1 and t2
what is the normal reaction force at the moment a particle leaves a surface?
0
what is the formula for finding the centre of mass?
x = [(mass1distance1) + (mass2distance2) + ….. ] / total mass
How to find the centre of mass of a triangle?
average the coordinates
COM using integration of a lamina
(integral of x*f(x)) / (integral of f(x))
COM of a solid of revolution
(integral of pixy^2) / (integral of pi*y^2)
what is the moment of a force?
Fdsin(x)
