the problems that harnessing wind for energy is the expense of large tracts of land in populated areas.
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1.Velocity (v) is a vector quantity that measures displacement (or change in position, Δs) over the change in time (Δt), represented by the equation v = Δs/Δt. Speed (or rate, r) is a scalar quantity that measures the distance traveled (d) over the change in time (Δt), represented by the equation r = d/Δt.
Answer:
There are four types of friction: static, sliding, rolling, and fluid friction. Static, sliding, and rolling friction occur between solid surfaces. Static friction is strongest, followed by sliding friction, and then rolling friction, which is weakest. Fluid friction occurs in fluids, which are liquids or gases.
Explanation:
Answer:
The maximum speed at which the car can safety travel around the track is 18.6m/s.
Explanation:
Since the car is in circular motion, there has to be a centripetal force
. In this case, the only force that applies for that is the static frictional force
between the tires and the track. Then, we can write that:

And since
and
, we have:

Now, if we write the vertical equation of motion of the car (in which there are only the weight and the normal force), we obtain:

Substituting this expression for
and solving for
, we get:

Finally, plugging in the given values for the coefficient of friction and the radius of the track, we have:

It means that in its maximum value, the speed of the car is equal to 18.6m/s.
Answer:
D.The striking foot pushes backward against the ground. The friction with the ground provides an equal and opposite force forward