First question: 800J
Second question: 20.4m
Answer:
A. If the sum of the external forces on an object is zero, then the object must be in equilibrium
Explanation:
Equilibrium, in physics, the condition of a system when neither its state of motion nor its internal energy state tends to change with time.
For a single particle, equilibrium arises if the vector sum of all forces acting upon the particle is zero.
the object is at equilibrium, then the net force acting upon the object should be 0 Newton. Thus, if all the forces are added together as vectors, then the resultant force (the vector sum) should be 0 Newton.
There are three types of equilibrium: stable, unstable, and neutral
Answer:

Explanation:
We can use the following kinematics equations to solve this problem:
.
Using the first one to solve for acceleration:
.
Now we can use the second equation to solve for the distance travelled by the airplane:
(three significant figures).
Answer:
No, The Moon, on the other hand, rotates once around its every 28 days, and once around the Earth in that same 28 days. The result of this combination is that the same side of the Moon is always facing the Earth.
Answer:
Hello there!
Explanation:
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as stream, creek, brook, rivulet, and rill.
hope this helps!