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3 years ago

Please help, it's super easy!

Physics

2 answers:

anzhelika [568]3 years ago

6 0

Answer:

I got the same thing as them aswell.

Explanation:

Alexandra [31]3 years ago

5 0

The moon's gravitational pull on Earth causes water to bulge on two sides of the Earth(#3)

https://scijinks.gov/tides/

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Donovan claims that the immune system works with other body systems. Is he correct? Explain.

djverab [1.8K]

Yes it does work with the other body system

8 0

3 years ago

Read 2 more answers

a refridgerator has a coefficient of performance equal to 4.2 how much work must be done on the refridgerator in order to remove

anastassius [24]

Answer:

60 J

Explanation:

Given That

Coefficient of performance, CoP = 4.2

Quantity of heat of the refrigerator, Q = 250 J

Work done by the refrigerator, W = ?

First, it should be noted that the Coefficient of Performance can be said to be, the ratio of the Heat required to the Work done by the system. Mathematically written as,

CoP = Q / W

Since we are already given the values from our question, we can plug it in as it's a pretty straightforward question

4.2 = 250 / W, making W subject of formula, we have

W = 250 / 4.2

W = 60J

Thus, the Work done by the refrigerator is 60 J

5 0

3 years ago

a ball is thrown in the air at 20 m/s. ignoring redistance, what is the speed when it returns to the level at which it was throw

inysia [295]

Ball is projected upwards with speed 20 m/s

now using kinematics

$v_f^2 - v_i^2 = 2 a\delta x$

here when ball returns back to same position.

total displacement of ball will be zero.

$v_f^2 - v_i^2 = 0$

$vf = vi$

So ball will return to initial position with same speed in opposite direction.

6 0

3 years ago

Using the superposition method, calculate the current through R5 in Figure 8-71

Natasha2012 [34]

by superposition method we can find current in R5

here first let say only 2V battery is present in the circuit

now the equivalent resistance to be found for which we can say

2.2 k ohm and 1 k ohm is connected in parallel

$r_1 = \frac{2.2 * 1}{2.2 + 1}$

$r_1 = 0.6875 k ohm$

now it is in series with 1 k ohm and then that part is in parallel with 2.2 k ohm

$r_2 = \frac{2.2* (1+0.6875)}{2.2 + (1+0.6875)}$

$r_2 = 0.95 k ohm$

now the current flowing through the battery is

$i = \frac{2}{1 + 0.95} = 1.02 mA$

now this will divide into R3 and R2 so current flowing in R3 will be

$i_1 = \frac{2.2}{2.2+1.6875}*1.02 = 0.58 mA$

now this will again divide in R4 and R5

so current in R5 will be

$i_5 = \frac{R_4}{R_4 + R_5}* i_1$

$i_5 = 0.18 mA$

now when only 3 V battery is present in the circuit

R1 and R2 is in parallel and then it is in series with R3

so parallel combination will be

$r_1 = \frac{1*2.2}{2.2 +1} = 0.6875k ohm$

also after its series with R3

$r_2 = 1 + 0.6875 = 1.6875 k ohm$

now it is in parallel with R5 on other side

$r_3 = \frac{1.6875 * 2.2}{1.6875 + 2.2} = 0.95 k ohm$

now current through the battery will be given as

$i = \frac{3}{1 + 0.95} = 1.53 mA$

now it is divide in r2 and R5

so current in R5 is given as

$i_5 = \frac{r_2}{r_2 + R_5}*i$

$i_5 = \frac{1.6875}{2.2 + 1.6875} * 1.53$

$i_5 = 0.67 mA$

now the total current in R5 will be given by super position which is

$i = 0.67 + 0.18 = 0.85 mA$

so there is 0.85 mA current through R5 resistance

8 0

3 years ago

2. An airplane traveling north at 220. meters per second encounters a 50.0-meters-per-second crosswind

Alex777 [14]

The resultant speed of the plane is (3) 226 m/s

Why?

We can calculate the resultant speed of the plane by using the Pythagorean Theorem since both speeds are perpendicular (forming a right triangle).

So, calculating we have:

$ResultantSpeed=\sqrt{VerticalSpeed^{2}+HorizontalSpeed^{2}}\\\\ResultantSpeed=\sqrt{(220\frac{m}{s})^{2}+50\frac{m}{s})^{2}$

$ResulntantSpeed=\sqrt{48400\frac{m^{2} }{s^{2} }+2500\frac{m^{2} }{s^{2} } } \\\\ResultantSpeed=\sqrt{50900\frac{m^{2} }{s^{2} }}=226\frac{m}{s}$

Hence, we have that the resultant speed of the plane is (3) 226 m/s

Have a nice day!

5 0

3 years ago