The work is being done in following cases:
A mover carries a box up a flight of stairs.
A mover carries a box across a room.
Wind blows a pool chair across the yard.
A weightlifter lifts a barbell off the ground.
These are the only cases in which work is being done. The Formula of Work is:
Work= Force applied x Distance moved.
In all of these cases force is being applied and the object on which the force is being applied move in a horizontal or Vertical direction. Thus Work is done !

Explanation:
Natural length of a spring is
. The spring is streched by
. The resultant energy of the spring is
.
The potential energy of an ideal spring with spring constant
and elongation
is given by
.
So, in the current problem, the natural length of the spring is not required to find the spring constant
.

∴ The spring constant of the spring = 
Answer: D
Experiment 1 has a confounding variable related to the mass of the rockets. Any variation in mass may cause a discrepancy in the distance traveled.
This is the answer to the question because:
- Both experiments do have a confounding variable.
- Experiment 1 doesn't have to stay constant.
- A double-blind experiment will not do anything to the placebo.
- High blood pressure people will not make the results confusing.
The answer has to be the option D. Hope this helps you!
Answer:
the magnitude of the magnetic force on the wire is 0.2298 N
Explanation:
Given the data in the question;
we know that, the magnitude of magnetic force is given as;
|F
| = I(
×
)
given that
I = 2.6 A
= 0.17
= 0.52
so we substitute
|F
| = 2.6( 0.17i" × 0.52j" )
|F
| = 0.2298 N
Therefore, the magnitude of the magnetic force on the wire is 0.2298 N
Answer:
An electron has a negative electric charge.