Mechanics

Question 1

Momentum? equation

Answer 1

mass x velocity

Question 2

Impulse? equation

Answer 2

= Force x time
= Change in Momentum

Question 3

Restitution (e)? equation

Answer 3

Separation/Approach

v2-v1/u1-u2

Question 4

What does it mean if Restitution (e) is 1?

Answer 4

No loss of energy

Question 5

What does it mean if Restitution (e) is 0?

Answer 5

Stuck together

Question 6

Work done? equation

Answer 6

Force x Distance

Question 7

Work done if force is horizontal over a distance?

Answer 7

Force x cos(theta) x distance

Question 8

Total work done? equal to?

Answer 8

Total Work Done= Change in Kinetic Energy

Question 9

Gravitational Potential Energy? equation

Answer 9

-Mass x 9.8 x distance
-work done against gravity (object is raised)

Question 10

Hooke’s law? Equation

Answer 10

Tension (T)= Lamda (λ) x Extension (x) / Natural Length (L)

Question 11

Elastic Potential Energy? equation

Answer 11

EPE= (λ x X^2) / 2 L

Question 12

Increase in Elastic Potential Energy?

Answer 12

Final EPE-Initial EPE

Question 13

What is Elastic Potential Energy the same as? (EPE)

Answer 13

EPE= Work Done stretching a string

Question 14

Power? equation

Answer 14

Power= Work Done (J) / Time (s)
= Driving Force x Velocity

Question 14

Angular Velocity (w)? units

Answer 14

rad/s

Question 15

rad/s to rev/s conversion?

Answer 15

2π rad/ sec = 1 rev/sec
1 rad / sec= 1/2π rev/sec

Question 16

Linear speed (v)? equation

Answer 16

Linear Speed (V)= Radius (r) x Angular Speed (w)

Question 17

Acceleration in circular motion? equation

Answer 17

Acceleration (a)= radius (r) x Angular Speed (w) ^2 a=r x w^2
= Linear Speed (v)^2 / Radius (r) a= v^2/r

Question 18

Tension for string in circle? equation

Answer 18

T = Mass (m) x Velocity (v^2) / radius (r) T = m x v^2 / r

Question 19

What is EPE lost equal to?

Answer 19

KE gained

Question 20

EPE lost?

Answer 20

Initial EPE - Final EPE

Question 21

When a string is stretched what happens to EPE?

Answer 21

-Increases , Increase in EPE = loss in KE or if dropped loss in PE (mgh)

Question 22

When a string is squashed what happens to EPE?

Answer 22

-Decreases, loss in EPE= Increase in KE

Question 23

Circular motion when does it cease? (when no more force exerted by sphere)

Answer 23

When T = 0

Question 24

What angle does circular motion complete circle

Answer 24

Theta equals 180 degrees
- Tension > 0

Question 25

Complete circle rod

Answer 25

Velocity Constant V>0 Theta is 180 degrees (no tension in a rod)

Question 26

Closest approach?

Answer 26

• AB
• d^2 of vector calculated
  -differentiate for t = 0
• sub t back into d^2 to find closest distance

Question 27

Collisions vector?

Answer 27

• AB
  -AB = 0
  -find t then sub into rA to find position of collision