Answer:
W = (F1 - mg sin θ) L, W = -μ mg cos θ L
Explanation:
Let's use Newton's second law to find the friction force. In these problems the x axis is taken parallel to the plane and the y axis perpendicular to the plane
Y Axis
N -
=
N = W_{y}
X axis
F1 - fr - Wₓ = 0
fr = F1 - Wₓ
Let's use trigonometry to find the components of the weight
sin θ = Wₓ / W
cos θ = W_{y} / W
Wₓ = W sin θ
W_{y} = W cos θ
We substitute
fr = F1 - W sin θ
Work is defined by
W = F .dx
W = F dx cos θ
The friction force is parallel to the plane in the negative direction and the displacement is positive along the plane, so the Angle is 180º and the cos θ= -1
W = -fr x
W = (F1 - mg sin θ) L
Another way to calculate is
fr = μ N
fr = μ W cos θ
the work is
W = -μ mg cos θ L
Answer:
8.1 N/49 N=0.1653 which means 16.53% of the weight of the object on Earth.
Explanation:
On the Moon, where the gravitational constant is 1.62
, the weight of the 5 kg object will be: 
Where the answer is in Newtons (N) since all quantities are given in the SI system.
On Earth, on the other hand, the weight of the object is:

Therefore the object's weight on the Moon compared to that on Earth will be:

That is, 16.53% of the weight the object has on Earth.
When I bump the table, the coffee in my cup spilled out. Newton's 1st law explains this reaction.
Answer: A) or the first option.