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6 days ago

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an ice skater is moving at a speed of 2 mi/hr when she slams into a wall 0.05 hours later. what is her acceleration?

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The ends of a cylindrical steel rod are maintained at two different temperatures. The rod conducts heat from one end to the othe

serg [3582]

Answer:20 cal/s

Explanation:

Given

Heat transfer rate is $\dot{Q}=10 cal/s$

Also heat rate is given by

$\dot{Q}=kA\frac{dT}{dx}$

where $k=thermal\ conductivity$

$A=area\ of\ cross-section$

$dT=change\ in\ temperature$

$dx=change\ in\ length$

$10=k\frac{\pi }{4}d^2\frac{dT}{L}----1$ For $d'=2d, Length L'=2L$

$\dot{Q}=k\frac{\pi }{4}(2d)^2\frac{dT}{2L}---2$

dividing 1 and 2 we get

$\frac{10}{\dot{Q}}=\frac{2d^2}{4d^2}$

$\dot{Q}=20 cal/s$

7 0

1 month ago

A student claims that earthquakes are more destructive than tsunamis. In one or two sentences, explain at least two reasons that

ValentinkaMS [3465]

An earthquake can impact individuals on land, causing greater destruction than a tsunami, which primarily affects those near the ocean.

8 0

2 months ago

A graph of the net force F exerted on an object as a function of x position is shown for the object of mass M as it travels a ho

Softa [3030]

The alteration in kinetic energy is $\Delta K = 3Fd$

Clarification:

According to the work-energy principle, the task performed on an object corresponds to the alteration in its kinetic energy. In mathematical terms:

$W=K_f -K_i= \Delta K$

where:

W signifies the work performed on the object

$K_f$ denotes the kinetic energy at the end

$K_i$ indicates the kinetic energy at the start

Furthermore, when the force is exerted in line with the object’s motion, the work done is expressed as:

$W=F\Delta x$

Here,

F represents the force’s magnitude

$\Delta x$ denotes the object’s displacement

In this scenario, the force impacting the object is

F

While the distance moved is the horizontal length traveled, hence

$\Delta x = 3d$

Consequently, the work accomplished is

$W=(F)(3d)=3Fd$

Thus, the alteration in kinetic energy amounts to

$\Delta K = 3Fd$

Learn more about work and kinetic energy:

5 0

2 months ago

A standard baseball has a circumference of approximately 23 cm . if a baseball had the same mass per unit volume as a neutron or

Softa [3030]

Answer:

Baseball mass: $m_b=3.992*10^{14}kg$

Explanation:

Circumference of a baseball is calculated using 2πr = 23 cm

Thus, the radius comes out to be 3.66 cm, which equals $3.66*10^{-2}$ m

The mass density of the baseball matches that of a neutron or proton.

Proton mass = $10^{-27}$ kg

Proton diameter = $10^{-15}$ m

Proton radius = $5*10^{-16}$ m

Volume of the baseball is $\frac{4}{3} \pi r^3$

Now by substituting all values into the mass per unit volume equation for the baseball, we get:

$\frac{m_b}{\frac{4}{3}\pi *(3.66*10^{-2})^3} =\frac{10^{-27}}{\frac{4}{3}\pi *(5*10^{-16})^3}$

$\frac{m_b}{(3.66*10^{-2})^3} =\frac{10^{-27}}{(5*10^{-16})^3}$

$m_b=3.992*10^{14}kg$

Therefore, the baseball mass amounts to $m_b=3.992*10^{14}kg$

5 0

2 months ago

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