Answer:
a) 
, b) 
Explanation:
a) Let consider two equations of equilibrium, the first parallel to ski slope and the second perpendicular to that. The equations are, respectively:
The force on the skier is:
b) The equations of equilibrium are the following:
The force on the skier is:
<span>First, she should put the sample in a test tube and place it in a centrifuge. This would cause the red blood cells to move to the bottom because of their higher density. Next, she would be able to decant the plasma and analyze it separately from the red blood cells.</span>
"6.5 km/hr" is not a velocity. It's just a speed, so
we don't know what direction he's walking.
If he happens to be walking north, then it takes him
(12 km) / (6.5 km/hr) = 1.846... hours (rounded) .
If he's walking in any other direction, it takes him longer than that.
If the angle between north and the direction he's walking is
90 degrees or more, then he can never cover any northward
distance, no matter how long he walks.
Explanation:
In a vacuum (no air resistance), it doesn't. All falling objects, regardless of mass, accelerate at the same rate.
However, when air resistance is taken into account, heavier objects indeed fall faster than lighter objects, provided they have the same shape and size. For example, a lead ball falls faster than a styrofoam ball.
To understand why, first look at what factors affect air resistance:
D = ½ρv²CA
where ρ is air density,
v is velocity,
C is drag coefficient,
and A is cross sectional area.
As falling objects accelerate, they eventually reach a maximum velocity where air resistance equals weight. This is called terminal velocity.
D = W
½ρv²CA = mg
v = √(2mg/(ρCA))
If we increase m while holding everything else constant, v increases. So two objects with the same size and shape but different masses will have different terminal velocities, with the heavier object falling faster.
Acceleration = velocity/ time
Acceleration = 0.7-0.3 /30= 0.01 m/s^2
Notice that velocity is calculated the final speed minus the initial !
