A horizontal force of 50 N is required to push a wagon across a sidewalk at a constant speed.

A gymnast does a one-arm handstand. The humerus, which is the upper arm bone between the elbow and the shoulder joint, may be ap

igor_vitrenko [27]

Answer:

$= 5.241 \times 10^{-5} m$

Explanation:

Given:

Length of cylinder is, L = 0.27 m

Outer radius of cylinder is, r_out = 1.12×10^{-2} m

Inner radius of cylinder is, r_in = 3.9×10^{-3} m

Mass of person, m = 60 kg

Young's modulus , Y = 9.4×10^9 N/m2

(a)

Compressional strain of humerous is,

$Strain = \frac{Stress}{Young's\ modulus}$

$\frac{\Delta L}{L_0} = \frac{\frac{F}{A}}{Y}$

$= \frac{(mg)}{\pi(r_out^2 - r_in^2 )Y}$

$= \frac{(60 kg)(9.8 m/s2 )}{(\pi)[( 1.12\times 10^{-2})^2 - (3.9\times 10^{-3} m)^2] (9.4\times 10^9 N/m2 )}[tex] [tex]= 1.80\times 10^{-4} m$

(b) Let assume that humerous is compressed by ΔL

Since, strain = ΔL/L0

$(1.80 \times 10^{-4} m) = ΔL / 0.29 m$

Thus,

$ΔL = (4.56 \times 10^{-4} m)(0.29 m)$

$= 5.241 \times 10^{-5} m$

7 0

3 years ago

A recent study found that electrons that have energies between 3.45 eV and 19.9 eV can cause breaks in a DNA molecule even thoug

vlada-n [284]

Answer:

The Minimum wavelength is $\lambda_{min}= 382.2nm$

The Maximum wavelength is $\lambda_{max}= 624.2nm$

Explanation:

From the question we are told that

The energy range is $E_r = 3.25eV \ and \ 19.9eV$

Considering $E = 19.9eV$

When a single photon is transferred to to an electron the energy obtained can be calculated as follows

$E = 19.9eV = 19.9 *1.6 *10^{-19}J$

This energy is mathematically represented as

$E = \frac{hc}{\lambda_{max}}$

Here h is the Planck's constant with value of $h= 6.625*10^{-34}J\cdot s$

c is the speed of light with value of $c = 3*10^8 m/s$

Substituting values and making $\lambda$ the subject of the formula

$\lambda_{max} = \frac{hc}{E}$

$= \frac{6.625*10^{-34} * 3.0*10^{8}}{19.9*1.6*10^{-19}}$

$\lambda_{max}= 624.2nm$

Considering $E = 3.25eV$

When a single photon is transferred to to an electron the energy obtained can be calculated as follows

$E = 19.9eV = 3.25 *1.6 *10^{-19}J$

This energy is mathematically represented as

$E = \frac{hc}{\lambda_{min}}$

Substituting values and making $\lambda$ the subject of the formula

$\lambda_{min} = \frac{hc}{E}$

$= \frac{6.625*10^{-34} * 3.0*10^{8}}{3.25*1.6*10^{-19}}$

$\lambda_{min}= 382.2nm$

3 0

3 years ago

In one cycle, a freezer uses 585 J of electrical energy in order to remove 1750 J of heat from its freezer compartment at 10.0 F

gtnhenbr [62]

Answer:

(a) 0.525

(b) 1750J

Explanation:

Coefficient of Performance (COP) = Q2/(Q1 - Q2)

Q1 = heat rejected to the surrounding = 1750J

Q2 = heat absorbed in the environment = 585K

COP = 585/(1700 - 585) = 585/1115 = 0.525

(b). Heat expelled to the surrounding (room) = 1750J

7 0

3 years ago

Scientists usually write reports about their investigations. Why do they do this?

worty [1.4K]

As for me, the reson why scientists usually write reports about their investigations is because they want to <span>d. to communicate their work to other scientist. As far as I am concerned in this sphere they have to get many other opnions besides their own in order to complete or expand one that they have made up. Hope it helps :)</span>

5 0

3 years ago

If the wind or current is pushing your boat away from the dock as you prepare to dock, which line should you secure first?

Akimi4 [234]

Answer:

Bow Line

Explanation:

If the wind or current is pushing your boat away from the dock, bow line should be secured first.

1- We should cast off the bow and stern lines.

2-With the help of an oar or boat hook, keep the boat clear of the dock.

3-Leave the boat on its own for sometime and let the wind or current carry the boat away from the dock.

4 - As you see there is sufficient clearance, shift into forward gear and slowly leave the area.

7 0

3 years ago