6. Further Mechanics Flashcards
What is an impulse?
- The change in momentum.
- given by Ft=p
Derive impulse from newtons second law?
F=ma
a=Δv/Δt
∴ F=Δ(mv)/Δt
∴ FΔt = Δmv = Δp
How would you go about conserving momentum in two dimensions?
Resolve the motion into components (along the perpendicular axis).
What is the difference between an elastic and inelastic collision?
Elastic: kinetic energy is conserved.
Inelastic: kinetic energy is not conserved (converted into/transferred from other forms).
Is an explosion elastic or inelastic?
Inelastic.
As the kinetic energy after is greater than before.
Derive Eₖ = p²/2m using formulas for kinetic energy and momentum.
Eₖ = ½mv² p = mv
v= p/m
∴ Eₖ = ½m(p²/m²)
= ½(p²/m)
= p²/2m
What is a radian?
- The angle in the sector of a circle when the arc length of that sector is equal to the radius of the circle.
What is angular displacement?
- The angle turned through in a given direction…
- in radians or degrees.
What is angular velocity?
- The angle an object moves through per unit time.
How do you calculate the angular velocity from the angular displacement?
Δθ/Δt