Their are lots of things that are not made by nature. FOOD ,WATER IRON , AND OTHER THINGS
Answer:
Those are the best electricity conductors that we can use to span large distances with large amounts of power. Its also alot cheaper to use copper wire than other kinds of metals. not to mention copper can bend easily and that makes the job of putting on wires alot faster and easier.
The mass on the left has a downslope weight of
W1 = 3.5kg * 9.8m/s² * sin35º = 19.7 N
The mass on the right has a downslope weight of
W2 = 8kg * 9.8m/s² * sin35º = 45.0 N
The net is 25.3 N pulling downslope to the right.
(a) Therefore we need 25.3 N of friction force.
Ff = 25.3 N = µ(m1 + m2)gcosΘ = µ * 11.5kg * 9.8m/s² * cos35º
25.3N = µ * 92.3 N
µ = 0.274
(b) total mass is 11.5 kg, and the net force is 25.3 N, so
acceleration a = F / m = 25.3N / 11.5kg = 2.2 m/s²
tension T = 8kg * (9.8sin35 - 2.2)m/s² = 27 N
Check: T = 3.5kg * (9.8sin35 + 2.2)m/s² = 27 N √
hope this helps. :)
True: Friction depends on the types of surfaces involved and how hard the surfaces push together.