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: work = 1,305kJ
Explanation:
angle= 30°
force= 1,500N
distance= 1,000m
The formula for work is : Work= force x distance, however there is an angle of 30° between the direction of force applied and the direction of motion, therefore force must be decomposed to its value on the horizontal axis which is the direction of motion by using the cosine of the very angle.
W= F×cos(α)×D
W= 1,500×cos (30)×1,000
W= 1,305kJ ( kilojoules)
Answer:
True
Explanation:
When a star has reached the main sequence stage, hydrogen is converted into helium by nuclear fusion, . Also, the gravity and pressure are balanced because the star does not radiate more heat than it generates. A star usually spends most of its lifetime at this stage.
The Zero Age Main Sequence is the period during the main sequence when a star stops contracting, and begin to fuse hydrogen in its core.
Answer:

Explanation:
It is given that,
Weight of the person on Earth, W = 818 N
Weight of a person is given by the following formula as :

g is the acceleration due to gravity on earth


m = 83.46 kg
The mass of an object is same everywhere. It does not depend on the location.
Let W' is the weight of the person on the surface of a nearby planet, W' = 5320 N
g' is the acceleration due to gravity on that planet. So,


So, the acceleration due to gravity on that planet is
. Hence, this is the required solution.