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3 years ago

Can you hellp me please

Physics

2 answers:

Anna71 [15]3 years ago

8 0

Answer: 1 is D, and 2 is A.

Explanation: In winter our day only last for say 9 hours instead of the sun still being up at 9:13 Central Time. 2. The tilt causes the four seasons. We are in late fall right now, so our days are already shorter, but not as short as in December. After that, hey get longer.

Agata [3.3K]3 years ago

6 0

Answer:

The answer is D.

Explanation: The northern hemisphere is more cooler, because it doesn't have much sunlight to warm it up.

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You drive on Interstate 10 from San Antonio to Houston, half the time at 75 km/h and the other half at 106 km/h. On the way back

r-ruslan [8.4K]

Answer:

Explanation:

a ) from San Antonio to Houston let distance be d km .

Average speed = total distance / total time

time = distance / speed

Total time = (d / 2 x 75 ) +( d / 2 x 106 )

= .0067 d + .0047 d

= .0114 d

Average speed = d / .0114 d = 87.72 km /h

b ) from Houston back to San Antonio

Total time = (d / 2 x 106 ) +( d / 2 x 75 )

= .0047 d + .0067 d

= .0114 d

Average speed = d / .0114 d = 87.72 km /h

c )

For entire trip :

total distance = 2d

total time = 2 x .0114 d

Average speed = 2 d / 2 x .0114 d

= 87.72 km /h .

4 0

3 years ago

a 28.7 KG sled is pulled forward with a 63 net force across the ground with MK equals 0.169 what is the acceleration of the sled

abruzzese [7]

Answer:

$0.54\ \text{m/s}^2$

Explanation:

F = Force on the sled = 63 N

m = Mass of sled = 28.7 kg

$\mu_k$ = Coefficient of kinetic friction = 0.169

g = Acceleration due to gravity = $9.81\ \text{m/s}^2$

The force balance of the system is given by

$F-\mu_k mg=ma\\\Rightarrow a=\dfrac{F-\mu_k mg}{m}\\\Rightarrow a=\dfrac{63-0.169\times 28.7\times 9.81}{28.7}\\\Rightarrow a=0.54\ \text{m/s}^2$

The acceleration of the sled is $0.54\ \text{m/s}^2$ .

5 0

3 years ago

A spherical balloon is made from a material whose mass is 3.30 kg. The thickness of the material is negligible compared to the 1

stellarik [79]

Answer:

563712.04903 Pa

Explanation:

m = Mass of material = 3.3 kg

r = Radius of sphere = 1.25 m

v = Volume of balloon = $\frac{4}{3}\pi r^3$

M = Molar mass of helium = $4.0026\times 10^{-3}\ kg/mol$

$\rho$ = Density of surrounding air = $1.19\ kg/m^3$

R = Gas constant = 8.314 J/mol K

T = Temperature = 345 K

Weight of balloon + Weight of helium = Weight of air displaced

$mg+m_{He}g=\rho vg\\\Rightarrow m_{He}=\rho vg-m\\\Rightarrow m_{He}=1.19\times \frac{4}{3}\pi 1.25^3-3.3\\\Rightarrow m_{He}=6.4356\ kg$

Mass of helium is 6.4356 kg

Moles of helium

$n=\frac{m}{M}\\\Rightarrow n=\frac{6.4356}{4.0026\times 10^{-3}}\\\Rightarrow n=1607.85489$

Ideal gas law

$P=\frac{nRT}{v}\\\Rightarrow P=\frac{1607.85489\times 8.314\times 345}{\frac{4}{3}\pi 1.25^3}\\\Rightarrow P=563712.04903\ Pa$

The absolute pressure of the Helium gas is 563712.04903 Pa

3 0

3 years ago

A child is riding a merry-go-round that has an instantaneous angular speed of 12 rpm. If a constant friction torque of 12.5 Nm i

sammy [17]

Answer:

$-0.25 rad/s^2$

Explanation:

The equivalent of Newton's second law for rotational motions is:

$\tau = I \alpha$

where

$\tau$ is the net torque applied to the object

I is the moment of inertia

$\alpha$ is the angular acceleration

In this problem we have:

$\tau = -12.5 Nm$ (net torque, with a negative sign since it is a friction torque, so it acts in the opposite direction as the motion)

$I=50.0 kg m^2$ is the moment of inertia

Solving for $\alpha$ , we find the angular acceleration:

$\alpha = \frac{\tau}{I}=\frac{-12.5 Nm}{50.0 kg m^2}=-0.25 rad/s^2$

3 0

3 years ago

Which of the following forms of electromagnetic waves is LEAST dangerous to the human body?

makkiz [27]

<span>Which of the following forms of electromagnetic waves is LEAST dangerous to the human body? B
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5 0

3 years ago

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