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Lynna [10]
2 years ago
13

A batter hits a fastball with a mass of 0.145 kg that was traveling at 40.0 m/s; the force exerted by the bat on the ball is 29

N. What is the time of contact with the ball in order to reverse its motion at its original speed?
Physics
1 answer:
Vika [28.1K]2 years ago
3 0

The force applies an acceleration in the reverse direction of

29 N = (0.145 kg) <em>a</em>   →   <em>a</em> = 200 m/s²

and in order to hit the ball back with speed 40.0 m/s, this acceleration is applied over time <em>t </em>such that

200 m/s² = (40.0 m/s - (-40.0 m/s)) / <em>t</em>   →   <em>t</em> = (80.0 m/s) / (200 m/s²) = 0.4 s

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Calculate the number of free electrons per cubic meter for some hypothetical metal, assuming that there are 1.3 free electrons p
boyakko [2]

Answer:

The number of free electrons per cubic meter is 7.61\times 10^{28}\ m^{-3}

Explanation:

It is given that,

The number of free electrons per cubic meter is, 1.3

Electrical conductivity of metal, \sigma=6.8\times 10^7\ \Omega^{-1}m^{-1}

Density of metal, \rho=10.5\ g/cm^3

Atomic weight, A = 107.87 g/mol

Let n is the number of  free electrons per cubic meter such that,

n=1.3\ N

n=1.3(\dfrac{\rho N_A}{A})

Where

\rho is the density of silver atom

N_A is the Avogadro number

A is the atomic weight of silver

n=1.3\times (\dfrac{10.5\ g/cm^3\times 6.02\times 10^{23}\ atoms/mol}{107.87\ g/mol})

n=7.61\times 10^{22}\ cm^{-3}

or

n=7.61\times 10^{28}\ m^{-3}

Hence, this is the required solution.

6 0
3 years ago
Is the angular position of the first-order spectrum small enough for sinθ≈θ to be a good approximation?.
vesna_86 [32]

Answer:

15 to 30 so anywhere in between there.

7 0
2 years ago
Emily and Gemma did a Reaction time lab. Emily dropped the ruler while Gemma tried to catch it. She caught the ruler 5 times and
dlinn [17]

The average reaction time of Gemma is 0.1564 seconds.

As we know, Gemma is catching the scale and Emily is dropping the scale.

The whole experiment is taking place under gravity, so the acceleration is constant.

As we know, the scale is dropped, it means that the initial velocity of the scale is zero.

We can use the equation of motion,

The equation is,

S = Ut + 1/2at²

Where,

S is the displacement, which is 0.12 m in our case,

U is initial velocity which is 0m/s because the stone is dropped,

t is the time taken, this is equal tot he reaction time here,

a is the acceleration due to gravity whose value is 9.8m/s.

Now, putting all the values,

0.12 = 1/2(9.8)(t)²

t² = 0.24/9.8

t = 0.1564 seconds.

Gemma reacts in 0.1564 seconds to catch the scale.

To know more about equation of motion, visit,

brainly.com/question/27821888

#SPJ1

3 0
1 year ago
Can someone help me with the physics problem?:
Mamont248 [21]
The work you put into something is the energy it has afterward (neglecting friction and other so-called non-conservative forces).  This is called the work-energy theorem.  Think of objects in a gravitational field as "energy piggy banks".  If you put X joules of energy into it, that energy will be there as potential energy, stored for later.  So if you do 144J of work to elevate the bucket from an initial position, what ever it is initially, the final gravitational energy is 144J greater than before.
6 0
3 years ago
Anyone can help?? I need it done before 9am please!!
Delicious77 [7]

Answer:

The answer is below

Explanation:

The equation for a linear line graph is given by:

y = mx + b, where y and x are variables, m is the slope of the graph and b is the y intercept (that is value of y when x is zero).

The slope (m) of a line passing through two points (x_1,y_1)\ and\ (x_2,y_2) is given by:

m=\frac{y_2-y_1}{x_2-x_1}

A) The first line passes through the point (0, 0) and (10, 60). It is represented as (time, velocity). Hence the slope is:

m=\frac{60 -0}{10-0}=6\ m/min^2

B) The second line passes through the point (10, 60) and (15, 60). Hence the slope is:

m=\frac{60 -60}{15-10}=0\ m/min^2

C) The third line passes through the point (15, 60) and (40, -40). Hence the slope is:

m=\frac{-40 -60}{40-15}=-4\ m/min^2

D) The third line passes through the point (40, -40) and (55, 0). Hence the slope is:

m=\frac{0 -(-40)}{55-40}=2.67\ m/min^2

6 0
3 years ago
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