Answer:
a) fr = 266.92 N, fy = 1300 N, b) μ = 0.36
Explanation:
a) This is a balancing act.
Let's write the rotational equilibrium relations, where the turning point is the bottom of the ladder and the counterclockwise rotations are positive
-w x - W x₂ + R y = 0 (1)
usemso trigonometry to find distances
cos 60.08 = x / 7.5
x = 7.5 cos 60.08
x = 3.74 m
fireman
cos 60.08 = x₂ / 4
x2 = 4 cos 60
x2 = 2 m
wall support
sin 60.08 = y / 15
y = 15 are 60.08
y = 13 m
we substitute in equation 1
R y = w x + W x2
R = (w x + W x2) / y
R = (500 3.74 +800 2) / 13
R = 266.92 N
now let's write the expressions for the translational equilibrium
X axis
R -fr = 0
R = fr
fr = 266.92 N
Y Axis
Fy - w-W = 0
fy = 500 + 800
fy = 1300 N
b) ask the friction coefficient
the firefighter's distance is
cos 60.08 = x₃ / 9.00
x₃ = 9 cos 60
x₃ = 5.28 m
from equation 1
R = (w x + W x₃) / y
R = 500 3.74 + 800 5.28) / 13
R = 468.769 N
we saw that
fr = R = 468.769
The expression for the friction force is
fr = μ N
in this case the normal is the ratio to pesos
N = Fy
N = 1300 N
μ N = fr
μ = fr / N
μ = 468,769 / 1300
μ = 0.36
Newton’s 2nd law states that Force is equal to
the product of mass (m) and acceleration (a):
F = m a --->
1
While in magnetic forces, force can also be expressed as:
F = q v B --->
2
where,
q = total charge
v = velocity = 45 cm / s = 0.45 m / s
B = the magnetic field = 85 T
First we solve for the total charge, q:
q = 3.8 × 10^-23 g (1 mol / 23 g) (6.022 × 10^23 electrons / mol) (1.602 ×
10^-19 C / electron)
q = 1.594 × 10^-19 C
We equate equations 1 and 2 then solve for acceleration a:
m a = q v B
a = q v B / m
a = [1.594 × 10^-19 C * 0.45 m / s * 85 T] / 3.8 × 10-26 kg
a = 160,437,862.2 m/s^2
Therefore the maximum acceleration of Na ions is about 160 × 10^6 m/s^2.
Answer:
D. 3 hours or more
Explanation:
The average 8- to 18-year-old spends at least D. 3 hours every day in front of a screen, performing little to no physical activity. This is because, instead of exercising and socializing with their peers, children and teenagers frequently talk, watch a lot of movies/shows, or play video games on their computers. Unfortunately, this is typically considerably more than three hours every day. Although some children still prefer physical activities over this, the bulk of the population does not.
Answer:
Option (A)
Explanation:
The green plants are capable of synthesizing their own food, in the presence of sunlight, CO₂ and water, and in return, liberates food and oxygen (O₂). This process is known as photosynthesis. This process is possible due to the presence of chlorophyll pigments on the plant leaves.
These green plants are also known as producers, because they are able to generate food for the consumers.
Thus, the correct answer is option (A).
1. A wheelchair ramp. Instead of using lifting force on the wheelchair, You use push or pull force on it.
2. A slide. Instead of throwing down an item, It uses gravitational potential energy make an object "move" down the slide.
3.A screw. It's reducing the force by twisting the screw out of something instead of pulling it out. (Sorry about my bad grammar).
