Answer:
C. The wheel with spokes has about twice the KE.
Explanation:
Given that
Mass , radius and the angular speed for both the wheels are same.
radius = r
Mass = m
Angular speed = ω
The angular kinetic energy KE given as
I=Moment of inertia for wheels
Wheel made of spokes
I₁ = m r²
Wheel like a disk
I₂ = 0.5 m r²
Now by comparing kinetic energy
KE₁= 2 KE₂
Therefore answer is C.
Answer:
E=7453.99 V/m
Explanation:
The electric field on the charged is given by
E= Kqx/(r^2 +x^2)^3/2
Where;
K= constant of Coulomb's law
q= magnitude of charge= 30.0×10^-9 C
r= radius of the rings= 5 cm or 0.05m
x= distance between the rings = 18cm = 0.18 m
Substituting values;
E= 9.0×10^9 × 30.0×10^-9 × 0.18 / [(0.05^2 + (0.18)^2]^3/2
E= 48.6/(2.5×10^-3 + 0.0324)^3/2
E= 48.6/(0.0025 + 0.0324)^3/2
E= 48.6/6.52×10^-3
E=7453.99 V/m
I haven't worked out the number, but it won't be necessary ... it's easy to pick the answer out of the choices that are given. ... The time (5 yrs) is less than the half-life (12.35 yrs), so more than half of the original sample (100mg) remains. Only one of the choices is more than 50 mg. (Can you find it ?)
Answer:
Explanation:
x = 2 cos wt = 2 cos 10t ; w = 10
velocity = dx/dt = -2 x 10 sin 10 t.=- 20 sin 10t
t = .4
velocity = -20 sin 10 x .4 = -20 sin 4 = -20 x -0.7568 = 15.136 cm /s
w = √ k / m = 10 = √ k / .05
k = 15.136 N/m