Ummmmmmmmmm is this what subject??????? Because I hv no idea unless u tell me a subject
Answer:
Explanation:
If I assume that the wind did not cause the plane to chage its velocity.
The plane will have a velocity of vp = (0*i + 100*j) km/h relative to ground
The cart has a velocity of vc = (0*i - 20*j) km/h relative to the plane
vc' = vc + vp
vc' = (0*i + 100*j) + (0*i - 20*j) = (0*i + 80*j) km/h relative to the ground.
If I assume that the wind move the plane:
The plane will have a velocity of vp = (-40*i + 100*j) km/h relative to ground
The cart has a velocity of vc = (0*i - 20*j) km/h relative to the plane
vc' = vc + vp
vc' = (-40*i + 100*j) + (0*i - 20*j) = (-40*i + 80*j) km/h relative to the ground.
In reality the wind would move the plane a little, not to the full speed of the wind, somewhere between these two values, but without more data it cannot be calculated.
Answer:
option (b)
Explanation:
According to the Pascal's law
F / A = f / a
Where, F is the force on ram, A be the area of ram, f be the force on plunger and a be the area of plunger.
Diameter of ram, D = 20 cm, R = 20 / 2 = 10 cm
A = π R^2 = π x 100 cm^2
F = 3 tons = 3000 kgf
diameter of plunger, d = 3 cm, r = 1.5 cm
a = π x 2.25 cm^2
Use Pascal's law
3000 / π x 100 = f / π x 2.25
f = 67.5 Kgf
Answer:
35 J
Explanation:
The man is holding the box: this means that he is applying a force vertically upward, to balance the weight of the box (which pushes downward).
Therefore, we can ignore the horizontal displacement of the man, because the force applied (vertically upward) is perpendicular to that displacement (horizontal), so the work done for that is zero.
So, only the vertical motion contributes to the work. The work done by the man is equal to the gain in gravitational potential energy of the box, so:
where
is the weight of the box
is the vertical displacement
Substituting, we find
Answer:
A free body diagram with 2 forces: the first pointing downward labeled F Subscript g Baseline 20 N and the second pointing upward labeled F Subscript air Baseline 20 N.
Explanation:
This is because at terminal velocity, the ball stops accelerating and the net force on the ball is zero. For the net force to be zero, equal and opposite forces must act on the ball, so that their resultant force is zero. That is F₁ + F₂ = 0 ⇒ F₁ = -F₂
Since F₁ = 20 N, then F₂ = -F₁ = -20 N
So, if F₁ points upwards since it is positive, then F₂ points downwards since it is negative.
So, a free body diagram with 2 forces: the first pointing downward labeled F Subscript g Baseline 20 N and the second pointing upward labeled F Subscript air Baseline 20 N best describes the ball falling at terminal velocity.
