Answer:
Rubber is an insulator.
Explanation:
Rubber is an insulator. Electricity will always travel "the path of least resistance." Rubber has a very high resistance, so electricity will go somewhere else to find ground.
The crate moves at constant velocity, this means that its acceleration is zero, so the net force acting on the crate is zero (Newton's second law).
There are only two forces acting on the crate: the force F applied by the worker and the frictional force, acting in the opposite direction:
, where
is the coefficient of friction and
is the mass of the crate. Since the net force should be equal to zero, the two forces must have same magnitude, so we have:
And so, this is the force that the worker must apply to the crate.
Answer:
q = 0.0003649123 m²/s = (3.65 × 10⁻⁴) m²/s
Explanation:
For laminar flow between two parallel horizontal plates, the volumetric flow per metre of width is given as
q = (2h³/3μ) (ΔP/L)
h = hydraulic depth = 4mm/2 = 2mm = 0.002 m
μ = viscosity of oil (SAE 30) at 15.6°C = 0.38 Pa.s
(ΔP/L) = 26 KPa/m = 26000 Pa/m
q = (2h³/3μ) (ΔP/L)
q = (26000) × (2(0.002³)/(3×0.38))
q = 0.0003649123 m²/s = (3.65 × 10⁻⁴) m²/s
6: Short way: it cannot be 2.5, 3, or 5 because up to 5 seconds it only has positive velocity so it must be moving forwards.
Long Way: Velocity is in m / s, multiply that by time (s) to get m or displacement. From 0->5 you have a triangle under the curve, (1/2)(5)(20) = 50 meters displaced positive, you need to then look when velocity is under the curve and use a similar equation to solve for the area but make the answer negative. Find the point where it equals -50 and that is where it will have returned.
Answer to 6: B
7. I cannot see the problem enough to answer this. Just know if the line is above 0 velocity is positive so it is moving the direction it started, when it goes below 0 velocity is negative so it is moving opposite direction it started.
8. Accelration is change in velocity. Whatever the slope of the velocity graph is acceleration. At t=8 the slope is 0 because it is not going up or down.
Answer to 8: A
