Answer:
a) P = 807.85 N, b) P = 392.15 N, c) P = 444.12 N
Explanation:
For this exercise, let's use Newton's second law, let's set a reference frame with the x-axis parallel to the plane and the direction rising as positive, and the y-axis perpendicular to the plane.
Let's use trigonometry to break down the weight
sin θ = Wₓ / W
cos θ = W_y / W
Wₓ = W sin θ
W_y = W cos θ
Wₓ = 1200 sin 30 = 600 N
W_y = 1200 cos 30 = 1039.23 N
Y axis
N- W_y = 0
N = W_y = 1039.23 N
Remember that the friction force always opposes the movement
a) in this case, the system will begin to move upwards, which is why friction is static
P -Wₓ -fr = 0
P = Wₓ + fr
as the system is moving the friction coefficient is dynamic
fr = μ N
fr = 0.20 1039.23
fr = 207.85 N
we substitute
P = 600+ 207.85
P = 807.85 N
b) to avoid downward movement implies that the system is stopped, therefore the friction coefficient is static
P + fr -Wx = 0
fr = μ N
fr = 0.20 1039.23
fr = 207.85 N
we substitute
P = Wₓ -fr
P = 600 - 207,846
P = 392.15 N
c) as the movement is continuous, the friction coefficient is dynamic
P - Wₓ + fr = 0
P = Wₓ - fr
fr = 0.15 1039.23
fr = 155.88 N
P = 600 - 155.88
P = 444.12 N
"D. Magnetic and electrical forces are similar because they are both related to the interactions between charged particles" best describes how the forces relate.
Answer:
The answer is C. Abundant natural resources
Explanation:
A is wrong because humans cause pollution, B is wrong because we use natural resources and their supply would deteriorate, and D is wrong because we already break down rainforests and they are getting smaller.
Answer:
∴ [T]=[WF−1V−1]
Hope this answer is right!!
Answer:
B) the change in momentum.
Explanation:
The impulse is defined as the product between the force applied on an object (F) and the duration of the collision (
):
(1)
We can rewrite the force by using Newton's second law, as the product between mass (m) and acceleration (a):

So, (1) becomes

Now we can also rewrite the acceleration as ratio between the change in velocity and change in time:
. If we substitute into the previous equation, we find

And the quantity
is equivalent to the change in momentum,
.