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2 years ago

A magnet is

Physics

1 answer:

pshichka [43]2 years ago

6 0

Answer:

A)an object whose electrons can be aligned in the same direction

Explanation:

Those materials produce magnetic field is known as magnet materials.A magnet is a object whose electrons are aligned in the same direction.

All ferromagnetic materials are magnetic materials. The examples magnetic materials are Co (Cobalt),Ni (Nickel) etc.We know that magnetic filed are produce by the current.

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NASA launches a probe with a mass of 15,000 kg to another planet more massive than Earth. Which statement is true about the prob

vivado [14]

Answer: The weight of the probe will increase.

8 0

2 years ago

(a) Consider the initial-value problem dA/dt = kA, A(0) = A0 as the model for the decay of a radioactive substance. Show that, i

murzikaleks [220]

Answer:

a) $t = -\frac{ln(2)}{k}$

b) See the proof below

$A(t) = A_o 2^{-\frac{t}{T}}$

c) $t = 3T \frac{ln(2)}{ln(2)}= 3T$

Explanation:

Part a

For this case we have the following differential equation:

$\frac{dA}{dt}= kA$

With the initial condition $A(0) = A_o$

We can rewrite the differential equation like this:

$\frac{dA}{A} =k dt$

And if we integrate both sides we got:

$ln |A|= kt + c_1$

Where $c_1$ is a constant. If we apply exponential for both sides we got:

$A = e^{kt} e^c = C e^{kt}$

Using the initial condition $A(0) = A_o$ we got:

$A_o = C$

So then our solution for the differential equation is given by:

$A(t) = A_o e^{kt}$

For the half life we know that we need to find the value of t for where we have $A(t) = \frac{1}{2} A_o$ if we use this condition we have:

$\frac{1}{2} A_o = A_o e^{kt}$

$\frac{1}{2} = e^{kt}$

Applying natural log we have this:

$ln (\frac{1}{2}) = kt$

And then the value of t would be:

$t = \frac{ln (1/2)}{k}$

And using the fact that $ln(1/2) = -ln(2)$ we have this:

$t = -\frac{ln(2)}{k}$

Part b

For this case we need to show that the solution on part a can be written as:

$A(t) = A_o 2^{-t/T}$

For this case we have the following model:

$A(t) = A_o e^{kt}$

If we replace the value of k obtained from part a we got:

$k = -\frac{ln(2)}{T}$

$A(t) = A_o e^{-\frac{ln(2)}{T} t}$

And we can rewrite this expression like this:

$A(t) = A_o e^{ln(2) (-\frac{t}{T})}$

And we can cancel the exponential with the natural log and we have this:

$A(t) = A_o 2^{-\frac{t}{T}}$

Part c

For this case we want to find the value of t when we have remaining $\frac{A_o}{8}$

So we can use the following equation:

$\frac{A_o}{8}= A_o 2^{-\frac{t}{T}}$

Simplifying we got:

$\frac{1}{8} = 2^{-\frac{t}{T}}$

We can apply natural log on both sides and we got:

$ln(\frac{1}{8}) = -\frac{t}{T} ln(2)$

And if we solve for t we got:

$t = T \frac{ln(8)}{ln(2)}$

We can rewrite this expression like this:

$t = T \frac{ln(2^3)}{ln(2)}$

Using properties of natural logs we got:

$t = 3T \frac{ln(2)}{ln(2)}= 3T$

8 0

2 years ago

Is there any difference between reflection and echo???

Fofino [41]

Answer:

reflection is the act of reflecting or the state of being reflected while echo is

reflection of sound waves from a surface back to the initial listener

6 0

2 years ago

Brutus, a champion weight lifter, raises 220 kg a distance of 3.10 m. (a) how much work is done by brutus lifting the weights? j

Nana76 [90]

A) work = force * distance
mass is not a force, weight is, so we have to find the weight of the block.
Weight = mg
Weight = (220kg)(9.8)
Weight = 2156N
Work = 2156N * 3.10m
work = 6683.6J
b) Since he is holding the weights, it's not moving, therefore, he doesn't do any work
c) The answer is still the same amount of work when he lifted them.
d) The answer is no since when he let go the weight, he doesn't apply any force to the weight.
e) P = work/time
P = 6683.6J / 2.1s
P = 3182.67 watts

3 0

2 years ago

malcom is doing a wheely on his motorcycle and moving at 20 m/s with a momentum of 6000 kg m/s when he lays her down. The mass o

rodikova [14]

Answer:

110 kg

Explanation:

The momentum of the Malcom+motorcycle system is given by:

$p=(m+M)v$

where

(m+M) is the total mass of the system, with

m = mass of Malcom

M = 190 kg (mass of the motorcycle)

v = 20 m/s velocity

Since we know the momentum:

p = 6000 kg m/s

We can re-arrange the equation to find the mass of Malcom:

$m=\frac{p}{v}-M=\frac{6000 kg m/s}{20 m/s}-190 kg=110 kg$

3 0

3 years ago