1. Draw the free body diagram for a parked car

A 50.0 kg piece of rock slides down the side of Mt. Etna. That part of the volcano slopes up at 30.0° (from the horizontal). If

vesna_86 [32]

Answer:

0.224

Explanation:

There are two forces acting on the rock along the direction parallel to the slope:

- The component of the weight parallel to the slope, down, given by

$mg sin \theta$

where

m = 50.0 kg is the mass of the rock

$g=9.8 m/s^2$ is the acceleration of gravity

$\theta=30^{\circ}$ is the angle of the slope

- The force of friction, up along the slope, given by

$F_f=\mu R$

where

$\mu$ is the coefficient of friction

R is the normal reaction

So the equation of the forces along the direction parallel to the slope is

$mg sin \theta - \mu R = ma$ (1)

where

$a=3.0 m/s^2$ is the acceleration

The normal reaction R can be found by looking at the equation of the forces along the direction perpendicular to the slope: in fact, we have that R balances the component of the weight perpendicular to the slope, so

$R=mg cos \theta$

And substituting into (1)

$mg sin \theta - \mu mg cos \theta = ma$

And solving for $\mu$ , we find the coefficient of friction:

$\mu = \frac{g sin \theta -a}{g cos \theta}=\frac{(9.8)(sin 30)-3.0}{(9.8)(cos 30)}=0.224$

7 0

4 years ago

A 2.0 mm diameter wire of length 20 m has a resistance of 0.25 ȍ. what is the resistivity of the wire?

olasank [31]

The relationship between resistance R and resistivity $\rho$ is
$R= \frac{\rho L}{A}$ (1)
where L is the length of the wire and A is the cross-sectional area.

In our problem, the radius of the wire is half the diameter: r=1 mm=0.001 m, so the cross-sectional area is
$A=\pi r^2 = \pi (0.001 m)^2=3.14 \cdot 10^{-6} m^2$
The length of the wire is L=20 m and the resistance is $R=0.25 \Omega$ .

By re-arranging equation (1), we can find the resistivity of the wire:
$\rho = \frac{RA}{L}= \frac{(0.25 \Omega)(3.14 \cdot 10^{-6} m^2)}{(20 m)} = 3.93 \cdot 10^{-8} \Omega \cdot m$

5 0

3 years ago

Which model could represent a neutral atom of oxygen?<br> A. 2<br> B. 4<br> C. 3<br> D. 1

Sergeu [11.5K]

Answer: D. 1

Explanation:

Choice 1 could represent a neutral atom of oxygen

4 0

3 years ago

Read 2 more answers

Cart 1 has an initial velocity and hits cart 2 which is stationary. after a perfectly inelastic collision, the combined carts ar

Tomtit [17]

Option(a) the mass of cart 2 is twice that of the mass of cart 1 is the right answer.

The mass of cart 2 is twice that of the mass of cart 1 is correct about the mass of cart 2.

Let's demonstrate the issue using variables:

Let,

m1=mass of cart 1

m2=mass of cart 2

v1 = velocity of cart 1 before collision

v2 = velocity of cart 2 before collision

v' = velocity of the carts after collision

Using the conservation of momentum for perfectly inelastic collisions:

m1v1 + m2v2 = (m1 + m2)v'

v2 = 0 because it is stationary

v' = 1/3*v1

m1v1 = (m1+m2)(1/3)(v1)

m1 = 1/3*m1 + 1/3*m2

1/3*m2 = m1 - 1/3*m1

1/3*m2 = 2/3*m1

m2 = 2m1

From this we can conclude that the mass of cart 2 is twice that of the mass of cart 1.

To learn more about inelastic collision visit:

brainly.com/question/14521843

#SPJ4

4 0

2 years ago

If you are doing a "rowing" motion, what muscle of the shoulder are you using?

Andrej [43]

The upper back muscles being worked while using a rowing machine .your upper trapezius and rhomboids located between your shoulder blades, and latissimus dorsi located beneath the armpits

6 0

3 years ago