Retarded physics problem

Ffr = µsFn
Ffr = 0.4 * m * 9.8 m/s^2
Ffr = 0.4 * 1kg * 9.8 m/s^2


Ffr / Fn = µs
Ffr / Fn = 0.4

F = m2 * a
||Ffr|| = m2 * 9.8 m/s^2
(m2 * 9.8 m/s^2) / (m1 * 9.8 m/s^2) = 0.4
m2 / m1 = 0.4

m2 = m1 * 0.4

Since d2 = d1 (density)...

l2 = l1 * 0.4
l2 = 1m * 0.4
l2 = 0.4m