Question

I don't understand this. A can filled with sand has a mass of 0.45kg is swung overhead in a horizontal circle of radius 0.6m at a constant rate of 2.5 revolutions per second. Find the angular momentum of
the rock.

Answer 1

moment of inertia times angular velocity
or
I * omega
here:
I = m r^2 = .45 (.36)

omega = 2.5 revs/s * 2 pi radians/rev
= 5 pi rad/s

so
angular momentum =
.45*.36* 2.5 * 2*pi kg m^2/s

or
angular momentum = R cross P
where R is radius and P is linear momentum
v = .6* 2.5*2 pi
P = m v = .45 * .6 * 2.5 * 2 pi
R *P = .45 * .36 * 2.5 * 2 pi again