Velocity is defined by rate of change in the position
which we can also write as
while acceleration is defined as rate of change in velocity
so acceleration and velocity both are rate of change in position and rate of change in velocity with respect to time respectively
out of all above statement the correct answer must be
<u>Acceleration equals change in velocity divided by time. </u>
Answer:
a) K = 0.63 J, b) h = 0.153 m
Explanation:
a) In this exercise we have a physical pendulum since the rod is a material object, the angular velocity is
w² =
where d is the distance from the pivot point to the center of mass and I is the moment of inertia.
The rod is a homogeneous body so its center of mass is at the geometric center of the rod.
d = L / 2
the moment of inertia of the rod is the moment of a rod supported at one end
I = ⅓ m L²
we substitute
w =
w =
w =
w = 4.427 rad / s
an oscillatory system is described by the expression
θ = θ₀ cos (wt + Φ)
the angular velocity is
w = dθ /dt
w = - θ₀ w sin (wt + Ф)
In this exercise, the kinetic energy is requested in the lowest position, in this position the energy is maximum. For this expression to be maximum, the sine function must be equal to ±1
In the exercise it is indicated that at the lowest point the angular velocity is
w = 4.0 rad / s
the kinetic energy is
K = ½ I w²
K = ½ (⅓ m L²) w²
K = 1/6 m L² w²
K = 1/6 0.42 0.75² 4.0²
K = 0.63 J
b) for this part let's use conservation of energy
starting point. Lowest point
Em₀ = K = ½ I w²
final point. Highest point
Em_f = U = m g h
energy is conserved
Em₀ = Em_f
½ I w² = m g h
½ (⅓ m L²) w² = m g h
h = 1/6 L² w² / g
h = 1/6 0.75² 4.0² / 9.8
h = 0.153 m
Answer:
9.73 x 10⁻¹⁰ m
Explanation:
According to Heisenberg uncertainty principle
Uncertainty in position x uncertainty in momentum ≥ h / 4π
Δ X x Δp ≥ h / 4π
Δp = mΔV
ΔV = Uncertainty in velocity
= 2 x 10⁻⁶ x 3 / 100
= 6 x 10⁻⁸
mass m = 0.9 x 10⁻¹⁵ x 10⁻³ kg
m = 9 x 10⁻¹⁹
Δp = mΔV
= 9 x 10⁻¹⁹ x 6 x 10⁻⁸
= 54 x 10⁻²⁷
Δ X x Δp ≥ h / 4π
Δ X x 54 x 10⁻²⁷ ≥ h / 4π
Δ X = h / 4π x 1 / 54 x 10⁻²⁷
=
= 9.73 x 10⁻¹⁰ m