Mechanics Flashcards
Momentum? equation
mass x velocity
Impulse? equation
= Force x time
= Change in Momentum
Restitution (e)? equation
Separation/Approach
v2-v1/u1-u2
What does it mean if Restitution (e) is 1?
No loss of energy
What does it mean if Restitution (e) is 0?
Stuck together
Work done? equation
Force x Distance
Work done if force is horizontal over a distance?
Force x cos(theta) x distance
Total work done? equal to?
Total Work Done= Change in Kinetic Energy
Gravitational Potential Energy? equation
-Mass x 9.8 x distance
-work done against gravity (object is raised)
Hooke’s law? Equation
Tension (T)= Lamda (λ) x Extension (x) / Natural Length (L)
Elastic Potential Energy? equation
EPE= (λ x X^2) / 2 L
Increase in Elastic Potential Energy?
Final EPE-Initial EPE
What is Elastic Potential Energy the same as? (EPE)
EPE= Work Done stretching a string
Power? equation
Power= Work Done (J) / Time (s)
= Driving Force x Velocity
Angular Velocity (w)? units
rad/s
rad/s to rev/s conversion?
2π rad/ sec = 1 rev/sec
1 rad / sec= 1/2π rev/sec
Linear speed (v)? equation
Linear Speed (V)= Radius (r) x Angular Speed (w)
Acceleration in circular motion? equation
Acceleration (a)= radius (r) x Angular Speed (w) ^2 a=r x w^2
= Linear Speed (v)^2 / Radius (r) a= v^2/r
Tension for string in circle? equation
T = Mass (m) x Velocity (v^2) / radius (r) T = m x v^2 / r
What is EPE lost equal to?
KE gained
EPE lost?
Initial EPE - Final EPE
When a string is stretched what happens to EPE?
-Increases , Increase in EPE = loss in KE or if dropped loss in PE (mgh)
When a string is squashed what happens to EPE?
-Decreases, loss in EPE= Increase in KE
Circular motion when does it cease? (when no more force exerted by sphere)
When T = 0
What angle does circular motion complete circle
Theta equals 180 degrees
- Tension > 0
Complete circle rod
Velocity Constant V>0 Theta is 180 degrees (no tension in a rod)
Closest approach?
- AB
- d^2 of vector calculated
-differentiate for t = 0 - sub t back into d^2 to find closest distance
Collisions vector?
- AB
-AB = 0
-find t then sub into rA to find position of collision
