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3 years ago

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A hungry hawk was preying on a lizard who was running northwards to get away from the low-flying hawk. If the lizard can run 8m

across water in 4s, what is the lizard's velocity? (Speed: D/T)

1 answer:

Anastaziya [24]3 years ago

8 0

Answer:

2m/s²

Explanation:

velocity = displacement (distance in a specified direction /time

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Write a message to Mr. Chang explaining why the groundwater heating system will warm the school more than the water heater syste

kari74 [83]

Explanation:

For, heating purposes more the quantity of water more will be the heating. Clearly, underground heating would have more water and hence, it will have edge over the water heater system.

Moreover, for things at the same temperature, the thing with more molecules has more total kinetic energy (thermal energy) than the thing with fewer molecules. The groundwater heating system uses heat from the heat stored naturally in groundwater or aquifers. Thus, saving the cost of power required to heat in normal water heater.

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3 years ago

Read 2 more answers

A pendulum of mass 5.0 kg hangs in equilibrium. A frustrated student walks up to it and kicks the bob with a horizontal force of

Phoenix [80]

Answer:

The length is $L = 6.206m$ and the angle is $\theta = 37.752^o.$

Explanation:

The period $T$ of the pendulum is related to its length $L$ by

$T = 2\pi \sqrt{\dfrac{L}{g} },$

where $g =9.8m/s^2$ is the acceleration due to gravity.

Solving for $L$ we get

$L = \dfrac{T^2g}{4\pi^2}$

putting in $T =5.0s$ and $g =9.8m/s^2$ we get:

$L = \dfrac{(5.0s)^2*9.8m/s^2}{4\pi^2}$

$\boxed{L = 6.206m.}$

There are two forces acting on the pendulum: The gravitational force $mg$ and the $F = 30N$ student's force. Therefore, the angular displacement $\theta$ that these forces give is

$sin(\theta ) = \dfrac{F}{mg}$

$\theta = sin^{-1}( \dfrac{F}{mg})$

putting in $F =30N$ , $m =5.0kg$ , and $g =9.8m/s^2$ we get

$\theta = sin^{-1}( \dfrac{30N}{5.0kg*9.8m/s^2})$

$\boxed{\theta = 37.752^o.}$

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3 years ago

At what distance does a 100 Watt lightbulb deliver the same power per unit surface area as a 75 Watt lightbulb produces 10 m awa

ch4aika [34]

Answer:

At 11.5 m

Explanation:

The power per unit area corresponds to the intensity, which is given by

$I=\frac{P}{4\pi r^2}$

where

P is the power

$4\pi r^2$ is the area irradiated at a distance r from the source (it corresponds to the surface area of a sphere of radius r)

Here we want the intensity of the two light bulbs to be the same, so

$I_1 = I_2\\\frac{P_1}{4 \pi r_1^2}=\frac{P_2}{4\pi r_2^2}$

where we have

P1 = 100 W is the power of the first light bulb

P2 = 75 W is the power of the second light bulb

r2 = 10 m is the distance from the second light bulb

Solving for r1, we find

$r_1 = r_2 \sqrt{\frac{P_1}{P_2}}= (10 m) \sqrt{\frac{100 W}{75 W}} = 11.5 m$

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2 years ago

A wooden ring whose mean diameter is 15.0 cm is wound with a closely spaced toroidal winding of 555 turns. Compute the magnitude

ruslelena [56]

Answer:

9.916\times 10^{-4}T

Explanation:

Diameter of toroid is 15 cm =0.15 m

So length of the toroid is $l=\pi d=3.14\times 0.15=0.471\ m$

Number of turns of the toriod is given as 555

Current through the toroid is 0.670 A

Magnetic field $B=\mu _0ni=\mu _0\frac{N}{L}i=4\pi \times 10^{-7}\times \frac{555}{0.471}\times 0.670=9.916\times 10^{-4}T$

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3 years ago

When velocity is positive and acceleration is negative, what happens to the object’s motion?

xenn [34]

Answer:

Option (D) : The object slows down.

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3 years ago