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2 years ago

You accidentally drop a book down a stairwell. Assuming no air resistance, How fast will the book be moving after 1.1 second?

Physics

2 answers:

vazorg [7]2 years ago

7 0

Answer: 10.8 m/s

Explanation: Rounding up

nlexa [21]2 years ago

3 0

It would be accelerating at -9.8 m/s^2 so it’s velocity would be equal to -9.8•1.1 so the answer is 10.78m/s

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Two men, Joel and Jerry, each pushes an object that are identical on a horizontal frictionless floor starting from rest. Joel an

Nataliya [291]

Answer:

The work done by Joel is greater than the work done by Jerry.

Explanation:

Let suppose that forces are parallel or antiparallel to the direction of motion. Given that Joel and Jerry exert constant forces on the object, the definition of work can be simplified as:

$W = F\cdot \Delta s$

Where:

$W$ - Work, measured in joules.

$F$ - Force exerted on the object, measured in newtons.

$\Delta s$ - Travelled distance by the object, measured in meters.

During the first 10 minutes, the net work exerted on the object is zero. That is:

$W_{net} = W_{Joel} - W_{Jerry}$

$W_{net} = F\cdot \Delta s - F\cdot \Delta s$

$W_{net} = (F-F)\cdot \Delta s$

$W_{net} = 0\cdot \Delta s$

$W_{net} = 0\,J$

In exchange, the net work in the next 5 minutes is the work done by Joel on the object:

$W_{net} = W_{Joel}$

$W_{net} = F\cdot \Delta s$

Hence, the work done by Joel is greater than the work done by Jerry.

7 0

3 years ago

For the wave of light you generated in the Part B, calculate the amount of energy in 1.0 mol of photons with that same frequency

Angelina_Jolie [31]

Answer:

2.7 J

Explanation:

The energy of one photon is given by

$E=hf$

where

h is the Planck constant

f is the frequency

For the photons in this problem,

$f=6.8\cdot 10^9 Hz$

So the energy of one photon is

$E_1=(6.63\cdot 10^{-34})(6.8\cdot 10^9 )=4.5\cdot 10^{-24} J$

The number of photons contained in 1.0 mol is

$N_A = 6.022\cdot 10^{23} mol^{-1}$ (Avogadro number)

So the total energy of $N_A$ photons contained in 1.0 mol is

$E=N_A E_1 =(6.022\cdot 10^{23})(4.5\cdot 10^{-24})=2.7 J$

3 0

3 years ago

A battery charges a parallel-plate capacitor fully and then is removed. The plates are immediately pulled apart. (With the batte

Assoli18 [71]

Answer:

<em>There will be an increase in potential difference.</em>

Explanation:

As we know that the potential difference depends upon the capacitance.

ΔV = Q/C

When battery is disconnected the charge remains constant on the plates but the capacitance decreases. As the capacitance has an inverse relation with the potential difference, there will be an increase in it.

In addition to that the potential difference can also be defined as the product of field and distance between the plates. As the charge is constant so the field is constant. Upon increasing the separation between the plates the potential difference will also increased.

4 0

3 years ago

Which graph shows the relationship between temperature, X, and kinetic energy, Y?

strojnjashka [21]

Answer: see the graph attached (straight line, passing through the origin and positive slope).

Justification:

1) Kinetic energy and temperature are in direct proportion. That means:

i) Being kinetic energy y and temperature x: y α x

ii) That implies: y = kx,where k is the constant of proportionality.

iii) The graph is a line that passes through the origin and has positive slope k (k = y / x).

2) The proportional relationship between kinetic energy (KE) and temperature (T) is shown by the Boltzman law, which states:

Average KE = [3 / 2] KT, where K is Boltzman's constant, whose graph is of the form shown in the figure attached.

5 0

3 years ago

Read 2 more answers

A ferry coming into port is sailing at 12 m/s. It takes 2.5km to come to rest in the port. Calculate the deceleration of the fer

pogonyaev

Answer: -0.0288 m/s^2

Explanation:

Let's suppose that the ferry decelerates at a constant rate A (deceleration is an acceleration in the opposite direction to the original motion of an object)

Then the acceleration equation of the ferry will be:

a(t) = -A

(the negative sign is because this acceleration is in the opposite direction with respect to the movement of the ferry)

To get the velocity equation of the ferry, we need to integrate with respect to the time, t, we will get:

v(t) = -A*t + v0

where v0 is the initial velocity of the ferry, v0 = 12m/s.

v(t) = -A*t + 12m/s

For the position equation of the ferry we need to integrate again over time:

p(t) = (-A/2)*t^2 + (12m/s)*t + p0

Where p0 is the initial position of the ferry, in this case, it can be zero, because it will depend on where we put the origin on our coordinate axis.

then p0 = 0m

P(t) = (-A/2)*t^2 + (12m/s)*t

The ferry will come to rest at the moment when it's velocity is equal to zero, this will happen when:

v(t) = 0m/s = -A*t + 12m/s

We need to find the value of t.

A*t = 12m/s

t = (12m/s)/A

Now we can replace this in the position equation because we know that the ferry needs 2.5 km or 2500 meters to come to rest.

p( (12m/s)/A) = 2500m = (-A/2)*( (12m/s)/A)^2 + (12m/s)*((12m/s)/A)

2500m = (-72 m^2/s^2)/A + (144m^2/s^2)/A

2500m = (72 m^2/s^2)/A

2500m*A = (72 m^2/s^2)

A = (72 m^2/s^2)/2500m = 0.0288 m/s^2

and the acceleration of the ferry was -A, then the acceleration of the ferry is:

-0.0288 m/s^2

4 0

2 years ago