The human body is 65% oxygen by mass. If a person has a mass of 75.0 kg, what is the mass oxygen in his body?

Calculate the binding energy e of the boron nucleus 11 5b (1ev=1.602×10−19j). express your answer in millions of electron volts

nignag [31]

<span>Depends on the precision you're working to. proton mass ~ 1.00728 amu neutron mass ~ 1.00866 amu electron mass ~ electron mass = 0.000549 amu Binding mass is: mass of constituents - mass of atom Eg for nitrogen: (7*1.00728)-(7*1.00866)-(7*0.000549) -14.003074 = 0.11235amu Binding energy is: E=mc^2 where c is the speed of light. Nuclear physics is usually done in MeV[1] where 1 amu is about 931.5MeV/c^2. So: 0.11235 * 931.5 = 104.6MeV Binding energy per nucleon is total energy divided by number of nucleons. 104.6/14 = 7.47MeV This is probably about right; it sounds like the right size! Do the same thing for D/E/F and recheck using your numbers & you shouldn't go far wrong :) 1 - have you done this? MeV is Mega electron Volts, where one electronVolt (or eV) is the change in potential energy by moving one electron up a 1 volt potential. ie energy = charge * potential, so 1eV is about 1.6x10^-19J (the same number as the charge of an electron but in Joules). It's a measure of energy, but by E=mc^2 you can swap between energy and mass using the c^2 factor. Most nuclear physicists report mass in units of MeV/c^2 - so you know that its rest mass energy is that number in MeV.</span>

7 0

2 years ago

A person holds a rifle horizontally and fires at a target. The bullet leaves the muzzle of the rifle with a velocity of 460 m/s.

Trava [24]

Answer:

the distance travelled from the bullet to the target is 391m

Explanation:

Hello! To solve this exercise we must follow the following steps.

1. the bullet travels with constant speed which means that the distance traveled to the target is given by the following equation

X=(V1)(T1)

$T1=\frac{X}{V1} =\frac{x}{460}$

where

X=target distance

V1=bullet speed=460m/s

T1=

time it takes for the bullet to reach the target

2. The distance the sound travels is given by the following equation (it is the same as the distance from the person to the target)

X=(V2)(T2)

$T2=\frac{X}{V2} =\frac{x}{340}$

X=

target distance

V2= speed of sound=340m/s

T2= time it takes the sound of the Bullet to return.

3. The total time it takes for the person to hear the bullet(T=2s) is the sum of the time it takes for the bullet to reach the target, plus the time it takes for the sound to reach the person, with the above we infer the following equation

T=T1+T2

2=T1+T2

4. Finally we use the equations found in step 1 and 2 to find the distance traveled using algebra.

$2=\frac{x}{340}+\frac{x}{460} \\x(\frac{1}{340} +\frac{1}{460} )=2\\\ X= \frac{2}{(\frac{1}{340} +\frac{1}{460} )} \\\\x=391m$

the distance travelled from the bullet to the target is 391m

3 0

2 years ago

A shopper pushes a grocery cart for a distance of 18m at a constant speed on level ground, against a 37.5N frictional force. he

goldfiish [28.3K]

d = distance to which the grocery cart is pushed = 18 m

f = frictional force = 37.5 N

θ = angle of force below the horizontal = 27.5 deg

W = gravitational force in downward direction

Θ = angle between gravitational force in down direction and displacement in horizontal direction = 90

U = work done on the cart by gravitational force

work done on the cart by gravitational force is given as

U = W d CosΘ

inserting the values

U = W (18) Cos90

U = 0 J

5 0

2 years ago

Question 2 Saved

Goshia [24]

Protons and/or neutrons

3 0

2 years ago

A construction worker moved a crate full of equipment 15,0 m using a constant force

Mkey [24]

Considering the definition of work and power, 157.5 W of power was developed.

<h3>Power</h3>

Power is defined as how fast work is done. That is, power is the amount of work done per unit of time:

$Power=\frac{work}{time}$

P is the power developed by the force that performs the work and its unit of measurement in the International System is Watts (W).

The unit of measurement of work in the International System is the Joule (J). The time during which the work is developed has the unit of measurement in the International System of seconds (s).

On the other side, work is defined as the force that is applied on a body to move it from one point to another.

When a net force is applied to the body or a system and this produces displacement, then that force is said to perform mechanical work. This work can be positive if the system gains energy or negative if the system loses energy.

The work is equal to the product of the force by the distance and by the cosine of the angle that exists between the direction of the force and the direction that travels the point or the object that moves.

In this case, the angle between the force and the displacement is 0 degrees. This is because the force and the displacement are in the same direction and sense, in the horizontal direction. So the cosine of 0 degrees will have a value of 1. Then work is equal to:

Work= force× distance

Being the force 105 N and the distance 15 meters, the work can be calculated as:

Work= 105 N× 15 meters

Solving:

Finally, being the time 10 seconds, the power can be calculated as:

$Power=\frac{1,575 J}{10 s}$