B Light waves travel faster than sound waves
If the surface is perfectly frictionless AND level ... no ups and downs ... then the puck never slows down or stops. There's nothing to make it do so. (Notice that "perfectly frictionless" means no air resistance either.)
Answer:
Newton states his second law of motion in terms of momentum: The net external force equals the change in momentum of a system divided by the time over which it changes or F = m*a. The change in momentum is the difference between the final and initial values of momentum. ... It is equal to the change in momentum.
Explanation:
<span>Answer:
First we need to find the acceleration.
torque on cylinder Ď„ = T * r where T is the string tension;
T = m(g - a) where a is the acceleration of the cylinder. Then
Ď„ = m(g - a)r
But also τ = Iα. For a solid cylinder, I = ½mr²,
and if the string doesn't slip, then α = a / r, so
τ = ½mr² * a/r = ½mra.
Since Ď„ = Ď„, we have
m(g - a)r = ½mra → m, r cancel, leaving
g - a = ½a
g = 3a/2
a = 2g/3 where g, of course, is gravitational acceleration.
We know that v(t) = a*t, so for our cylinder
v(t) = 2gt / 3 â—„ linear velocity
and ω = v(t) / r = 2gt / 3r ◄ angular velocity</span>