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3 years ago

A stone is thrown horizontally at a velocity of 12.38 m/s from a tree house that is

Physics

1 answer:

andrew11 [14]3 years ago

6 0

Answer:

34.8 m/s

Explanation:

Since we're only interested in vertical velocity we can ignore anything horizontal.

We have the following information (in the vertical direction)

d = 61.8

a = 9.8

vi = 0

vf = ?

The equation combining all these variables is:

$v_f^2 = v_i^2 + 2ad\\v_f^2=0+2(9.8)(61.8)\\v_f^2=1211.28\\v_f=\sqrt{1211.28}\\v_f=34.8$

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A scientist is using an objective lens with 40X magnification on his microscope. If the ocular lens magnifies 10X, what is the t

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Answer:

400x

Total magnification = 40 × 10= 400x

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2 years ago

Identify two ways in which friction is not useful in science

kiruha [24]

Answer:

Friction between brakes and the wheels of a car or bicycle helps the vehicles slow down.
If you do not lubricate your bike regularly with oil, the friction in the chain and axles increases.

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2 years ago

The manufacturer of a 6V dry-cell flashlight battery says that the battery will deliver 15 mA for 60 continuous hours. During th

Vaselesa [24]

Answer:

16200 J

Explanation:

t = Time the battery is on = 60 hours

I = Current = $15\times 10^{-3}\ A$

Average voltage

$V=\dfrac{6+4}{2}=5\ V$

Energy is given by

$E=V\times I\times t$

$\\\Rightarrow E=5\times 15\times 10^{-3}\times 60\times 3600$

$\\\Rightarrow E=16200\ J$

The energy delivered in the given time is 16200 J

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3 years ago

Heredity appears to have a large effect on the intelligence of adults than environment. True False

Annette [7]

I JUST WANT THE ANSWER

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2 years ago

A hot (70°C) lump of metal has a mass of 250 g and a specific heat of 0.25 cal/g⋅°C. John drops the metal into a 500-g calorimet

Gnom [1K]

Answer:

d. 37 °C

Explanation:

$m_{m}$ = mass of lump of metal = 250 g

$c_{m}$ = specific heat of lump of metal = 0.25 cal/g°C

$T_{mi}$ = Initial temperature of lump of metal = 70 °C

$m_{w}$ = mass of water = 75 g

$c_{w}$ = specific heat of water = 1 cal/g°C

$T_{wi}$ = Initial temperature of water = 20 °C

$m_{c}$ = mass of calorimeter = 500 g

$c_{c}$ = specific heat of calorimeter = 0.10 cal/g°C

$T_{ci}$ = Initial temperature of calorimeter = 20 °C

$T_{f}$ = Final equilibrium temperature

Using conservation of heat

Heat lost by lump of metal = heat gained by water + heat gained by calorimeter

$m_{m} c_{m} (T_{mi} - T_{f}) = m_{w} c_{w} (T_{f} - T_{wi}) + m_{c} c_{c} (T_{f} - T_{ci}) \\(250) (0.25) (70 - T_{f} ) = (75) (1) (T_{f} - 20) + (500) (0.10) (T_{f} - 20)\\T_{f} = 37 C$

6 0

3 years ago