How fr do you think you would go on a car while sneezing for 2.5 seconds ?

A 15.0-m uniform ladder weighing 500 N rests against a frictionless wall. The ladder makes a 60.08 angle with the horizontal. (a

grigory [225]

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

7 0

3 years ago

The two forces acting on a skydiver are __________ and air _____________.

Stolb23 [73]

Answer:

Gravity and

Air resistance

Explanation:

The two forces acting on a skydiver are gravitational force and air resistance.

Gravitational force is a force that tends to pull all massive bodies towards the center of the earth. It works on all bodies that has mass. The larger or bigger the mass, the more the pull of gravity on the body.

Air resistance is the drag of air on a body as it passes to it. It is resisting force.

When a sky diver jumps out of a plane, he/she encounters both gravity and air resistance.
It soon balances both force and attain terminal velocity.
Air resistance is a frictional force that opposes motion.
This frictional force pushes in the opposite direction of motion
Motion direction is downward due to the celerity caused by gravity.

3 0

3 years ago

Read 2 more answers

Carter pushes a bag full of basketball jerseys across the gym floor. The he pushes with a constant force of 21 newtons. If he pu

Zolol [24]

Carter needs a power equal to 63 W to be able to push the bag full of Jersey. This is by using the formula: Power is equal to the product of Force applied and Displacement all over time traveled.

8 0

3 years ago

Read 2 more answers

An explorer is caught in a whiteout (in which the snowfall is so thick that the ground cannot be distinguished from the sky) whi

Veronika [31]

Answer:

$s=5.79\ km$

$\theta=47^{\circ}$ east of south

Explanation:

Given:

distance of the person form the initial position, $d'=8.4\ km$

direction of the person from the initial position, $47^{\circ}$ north of east

distance supposed to travel form the initial position, $d=5.3\ km$

direction supposed to travel from the initial position, due North

Now refer the schematic for visualization of situation:

$y=d'.\sin47^{\circ}-d$

$y=8.4\times \sin47-5.3$ ...............(1)

$x=d'.\cos47^{\circ}$

$x=8.4\times \cos47^{\circ}$ .................(2)

Now the direction of the desired position with respect to south:

$\tan\theta=\frac{y}{x}$

$\tan\theta=\frac{8.4\times \sin47}{8.4\times \cos47}$

$\theta=47^{\circ}$ east of south

Now the distance from the current position to the desired position:

$s=\sqrt{x^2+y^2}$

$s=\sqrt{(8.4\times \cos47)^2+(8.4\times \sin47-5.3)^2}$

$s=5.79\ km$

4 0

3 years ago

Why do hot stars look bluer than cool stars?

brilliants [131]

Answer:

(B) The wavelength that a star radiates the most energy is inversely proportional to the temperature.

Explanation:

As we know that

According to Wien's law wavelength is inverse proportional to the temperature .

λ.T = Constant.

λ.∝ 1 /T

As we know that star radiates wavelength and this wavelength is inverse proportional to the temperature of the star.

The temperature of cool star is cooler than the temperature of hot star that is cool star looks red and hot star looks blue.Cool star have low energy and hot star have high energy.

So option B is correct.

(B) The wavelength that a star radiates the most energy is inversely proportional to the temperature.

5 0

3 years ago