False as oxygen is the second most abundant and nitrogen is the most abundant at 78%.
The general formula to calculate the work is:

where F is the force, d is the displacement of the couch, and
is the angle between the direction of the force and the displacement. Let's apply this formula to the different parts of the problem.
(a) Work done by you: in this case, the force applied is parallel to the displacement of the couch, so
and
, therefore the work is just equal to the product between the horizontal force you apply to push the couch and the distance the couch has been moved:

(b) work done by the frictional force: the frictional force has opposite direction to the displacement, therefore
and
. Therefore, we must include a negative sign when we calculate the work done by the frictional force:

(c) The work done by gravity is zero. In fact, gravity (which points downwards) is perpendicular to the displacement of the couch (which is horizontal), therefore
and
: this means
.
(d) Work done by the net force:
The net force is the difference between the horizontal force applied by you and the frictional force:

And the net force is in the same direction of the displacement, so
and
and the work done is

Answer:
The correct answer is option D i.e. A and C
Explanation:
The correct answer is option D i.e. A and C
for proficient catching player must
- learn to absorbed the ball force
- moves the hang according to ball direction to hold the ball
- to catch ball at high height move the finger at higher position
- to catch ball at low height move the finger at lower position
Answer:
Part a)

Part b)

Explanation:
As we know that mountain climber is at rest so net force on it must be zero
So we will have force balance in X direction


now we will have force balance in Y direction


Part a)
so from above equations we have



Part b)
Now for tension in right string we will have

