Physics Test 4

Question 1

Torque equation

Answer 1

T = F * r

Question 2

Sign of clockwise rotation?

Answer 2

Negative

Question 3

Sign of counterclockwise rotation?

Answer 3

Positive

Question 4

Torque is measured by the distance of the force to the

Answer 4

moment arm

Question 5

Static equilibrium

Answer 5

ΣT = 0 and ΣF = 0

Question 6

inertia for a solid disk

Answer 6

(1/2) * MR^2

Question 7

how do we get to the Torque equation?

Answer 7

F = ma
Fr = mar (T = Fr)
T = m(αr)r (αr = a)
T = α * mr^2
optionally T = Iα (mr^2 = I)

Question 8

linear velocity equation given angular velocity

Answer 8

v = ωr therefore (v / r) = ω

Question 9

Angular velocity given frequency or period

Answer 9

ω = 2πf or ω = 2π/T

Question 10

How do we get centripetal acceleration?

Answer 10

a = v^2 / r
a = (ωr)^2 / r (ωr = v)
a = ω^2 / r

Question 11

linear speed around a point

Answer 11

v = d / t where d = 2pir

Question 12

angular speed

Answer 12

ω = θ / t

Question 13

equation connecting liner speed and angular speed

Answer 13

v = rω

Question 14

Ratio relating periods of orbiting masses

Answer 14

( T1 / T2 )^2 = ( r1 / r2 )^3

Question 15

Ratio using the mass of the object being orbited

Answer 15

G Mc T^2 = 4 π^2 r^3