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3 years ago

8

Physics

1 answer:

VashaNatasha [74]3 years ago

5 0

Answer:

table and graph are attached

Explanation:

a) The velocity of the ball will be ...

v(t) = v0 -at

v(t) = 19.6 -9.8t

The position of the ball will be the integral of this:

h(t) = ∫v(t)·dt = 19.6t -(1/2)(9.8t^2)

The attached table calculates the vertical position in meters for the required times.

b) Graphs of displacement (h(t)) and velocity (h'(t)) are shown in the attachment.

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If a runner exerts 350 J of work to make 125 W of power, then how long did it take the runner to do the work?

PilotLPTM [1.2K]

225 is the correct answer

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3 years ago

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Neglecting air resistance, which of the following statements is true regarding an object in freefall?Lector inmersivo A. An obje

Dafna1 [17]

Answer:

E. An object’s velocity changes at a constant rate, and its acceleration remains constant.

Explanation:

When an object is in freefall, it implies that the object is falling freely under gravity. If it falls towards the earth surface, the fall is in the direction of the Earth's gravitational force.

At the point of release of the object, its initial velocity is zero because it is at rest. But when released, its velocity increases at a constant rate until it is acted upon by an external force. But its acceleration remains constant, acceleration due to gravity.

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4 years ago

When 0.1375 g of solid magnesium is burned in a constant-volume bomb calorimeter, the temperature increases by 1.126°C. The heat

Bumek [7]

Answer:

-24.76 kJ/mol

Explanation:

given,

mass of solid magnesium burned = 0.1375 g

the temperature increases by(ΔT) 1.126°C

heat capacity of of bomb calorimeter (C_{cal})= 3024 J/°C

heat absorbed by the calorimeter

$q_{cal} = C_{cal}\DeltaT$

$q_{cal} = 3024 \times 1.126$

$q_{cal} =3405.24\ J$

$q_{cal} =3.405\ kJ$

heat released by the reaction

$q_{rxn} = -q_{cal}$

$q_{rxn} = -3.405\ kJ$

energy density will be equal to heat released by the reaction divided by the mass of magnesium

Energy density = $\dfrac{-3.405}{0.1375}$

Energy density = -24.76 kJ/mol

heat given off by burning magnesium is equal to -24.76 kJ/mol

6 0

3 years ago

A rotating object has an angular acceleration of α = 0 rad/s2. Which one or more of the following three statements is consistent

Murrr4er [49]

Answer:

A,B and C

Explanation:

Statement A

At all times, angular velocity is $\omega = 0\,{\rm{rad/s}$

Angular acceleration is the rate of change in angular velocity with respect to time.

Angular velocity and angular acceleration are related by

${\omega _{\rm{f}}} = {\omega _{\rm{i}}} + \alpha t$

Which when re-arranged becomes

$\alpha = \frac{{{\omega _{\rm{f}}} - {\omega _{\rm{i}}}}}{t}$

There’s no change in angular velocity anytime when the angular velocity is $\omega = 0\,{\rm{rad/s}}$

The equation can be modified as follows:

$\begin{array}{c}\\\alpha = \frac{{0\,{\rm{rad/s}} - 0\,{\rm{rad/s}}}}{t}\\\\ = 0\\\end{array}$

Therefore, the angular acceleration becomes zero hence statement A is valid.

Statement B

Angular acceleration is the rate of change in angular velocity with respect to time.

Angular velocity and angular acceleration are related by

${\omega _{\rm{f}}} = {\omega _{\rm{i}}} + \alpha t$

Which when re-arranged becomes

$\alpha = \frac{{{\omega _{\rm{f}}} - {\omega _{\rm{i}}}}}{t}$

There’s no change in angular velocity anytime when the angular velocity is $\omega = 10\,{\rm{rad/s}}$ .The final and initial velocities remain the same.

The equation can be modified as follows:

$\begin{array}{c}\\\alpha = \frac{{10\,{\rm{rad/s}} - 10\,{\rm{rad/s}}}}{t}\\\\ = 0\\\end{array}$

Therefore, the angular acceleration becomes zero and statement B is valid

Statement C

Angular velocity is defined as the change in the angular position with respect to time.

Angular velocity and angular displacement are related by

$\theta = \omega t$

Which can also be modified as:

${\theta _{\rm{f}}} - {\theta _{\rm{i}}}$

Note that the final position is ${\theta _{\rm{f}}}$ and initial position is ${\theta _{\rm{i}}}$

Modifying the equation to find the angular velocity we obtain

$\omega = \frac{{{\theta _{\rm{f}}} - {\theta _{\rm{i}}}}}{t}$

When the angular displacement has the same value at all times, the equation becomes

$\begin{array}{c}\\\omega = \frac{{{\theta _{\rm{i}}} - {\theta _{\rm{i}}}}}{t}\\\\ = 0\\\end{array}$

The angular velocity becomes zero.

Angular acceleration and angular velocity are related by

${\omega _{\rm{f}}} = {\omega _{\rm{i}}} + \alpha t$

The expression above can be rearranged as follows:

$\alpha = \frac{{{\omega _{\rm{f}}} - {\omega _{\rm{i}}}}}{t}$

At all times, the angular velocity is $\omega = 0\,{\rm{rad/s}}$ hence initial and final velocities remain the same

We obtain

$\begin{array}{c}\\\alpha = \frac{{0\,{\rm{rad/s}} - 0\,{\rm{rad/s}}}}{t}\\\\ = 0\\\end{array}$

Therefore, the angular acceleration becomes zero and statement C is valid.

Therefore, statements A,B and C are consistent .

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4 years ago

True<br> False<br><br> PLEASE HELP

harkovskaia [24]

Answer:

False

Explanation:

10 is not the same as -10 but if -10 is the absolute value they would be the same

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3 years ago