While plane is moving under tailwind condition it took time "t"
so here we will have

here net speed of the plane will be given as


similarly when it moves under the condition of headwind its net speed is given as

now time taken to cover the distance is 2 hours more

now solving two equations

solving above for v_w we got

Answer:
The average speed for the entire run is 12 km/h.
Explanation:
The average speed is given by the following equation:

Where:
: is the total distance
: is the total time
If during the first hour, they ran a total of 13 kilometers and then, they ran 5.0 kilometers during the next half an hour we have:


Hence, the average speed is:

Therefore, the average speed for the entire run is 12 km/h.
I hope it helps you!
Answer:
As ice melts into water, kinetic energy is being added to the particles. This causes them to be 'excited' and they break the bonds that hold them together as a solid, resulting in a change of state: solid -> liquid.
Explanation:
A. A stretched catapult can do work when released so it must have potential energy.
b. A stone on the ground will not move on its own ever again so it has zero energy.
c. In order to roll an object there must be a friction force between the object and the ground (otherwise it will slide)
d. To lift a stone you must overcome the weight which is the force due to gravity.
e. Work and energy are both measured in Joules.