The answer is A because potential energy is stored up energy which means that it’s not moving
Answer: D. The force and displacement are in the same direction.
Explanation:
The Work 
done by a Force 
refers to the release of potential energy from a body that is moved by the application of that force to overcome a resistance along a path with distance 
.
Work is a scalar magnitude, and its unit in the International System of Units is the Joule (like energy).
Now, when the applied force is constant and the direction of the force and the direction of the displacement are <u>parallel</u>, the equation to calculate it is:
(1)
When they are not parallel, both directions form an angle, let's call it 
. In that case the expression to calculate the Work is:
(2)
When the force and displacement are perpendicular to each other,
and <u>no work is done</u>.
Answer:
Average speed of Elain = 60 km/h
Explanation:
Total Distance covered by Jack = 360km
Average Speed of Jack = 80 km/h
Time taken by Jack to complete his journey = Distance / Average speed = 360 km / 80 km/h
Time taken by Jack to complete his journey = 4.5 hours
As it is given the both Jack and Elain travelled the same amount of distance:
Total distance travelled by Elain = 360 km
It is given that Elain took 1.5 hourse more than Jack to cover the distance, so Time taken by Elain to cover the distance is = 4.5 hours + 1.5 hours = 6 hours
Average speed of Elain = Distance/ time = 360 km / 6 hours
Average speed of Elain = 60 km/h
The speed of sound is 340.29 meters per second.
Knowing that, we can calculate how high this cliff is by 340.29 * .4
The cliff is 340.29 * .4 = 136.12 meters
