Answer:

Explanation:
Formula for AVERAGE acceleration

is Final Velocity
is Initial Velocity
is Final Time
is Initial Time
Most of the time, the initial time will be 0, so you won't have to subtract.
<h2>Diagonal of circle </h2>
Explanation:
As the skateboarder wants to cross the play ground . The surface is rough .
As we know , the force of friction is non-conservative force . Thus work is required against this force .
We have formula:
work done = Force x distance (in one direction )
Te force applied cannot be changed , so he is to decrease the distance .
In case of circle , diameter is the minimum distance . Thus he is supposed to move along it .
Answer:


Explanation:
When coefficient of friction is approximately zero then we have



here we know that

R = 30 m


now when friction coefficient is 0.30 then we have


now we have




Answer:
Reflective
Explanation:
The radiation pressure of the wave that totally absorbed is given by;

and While the radiation pressure of the wave totally reflected is given by;

Now compare the two-equation you can clearly see that the pressure due to reflection is larger than absorption therefore the sail should be reflective.