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3 years ago

B. Complete the lists:

Physics

1 answer:

d1i1m1o1n [39]3 years ago

6 0

Answer:

Things you should do for your family

help your parents
treat them kindly
listen and obey them
appreciate them for anything they do for you
talk softly

things you shouldn't

backanswering them
Disobey
And anything that's harsh or make it parents sad

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An object is released from rest at time t = 0 and falls through the air, which exerts a resistive force such that the accelerati

rosijanka [135]

Answer:

A) $\frac{g}{b}(1-e^{-bt})$

Explanation:

Since a = g - bv,

We can substitute a = dv/dt into the equation.

Then, the equation will be like dv/dt = g - bv.

So we got first order differential equation.

As known, v = 0 at t = 0, and v = g/b at t = ∞.

Since $\frac{dv}{dt}= g - bv = b( \frac{g}{b} - v)$ ⇒ $\frac{dv}{ \frac{g}{b} - v}= bdt$

So take the integral of both side.

$- ln (\frac{g}{b} - v) = bt + C$

Since for t=0, v = 0 ⇒ $C =- ln (\frac{g}{b})$

$v = \frac{g}{b} + e^{-bt-ln(\frac{g}{b})} = \frac{g}{b}- \frac{g}{b}e^{-bt} = \frac{g}{b}(1-e^{-bt})$

5 0

3 years ago

The denser a substance, the more tightly packed it is. The table below shows the volume and mass of two different substances. Co

trasher [3.6K]

Answer:

Both objects are packed equally tightly.

Explanation:

For Substance R we have

mass = 10 g

Volume = 22 cubic cm

So we know that density is defined as

$\rho = \frac{m}{V}$

here we have

$\rho = \frac{10 g}{22 cm^3}$

$\rho = 0.454 g/cm^3$

For substance S we have

mass = 25 g

Volume = 55 cubic cm

So we know that density is defined as

$\rho = \frac{m}{V}$

here we have

$\rho = \frac{25 g}{55 cm^3}$

$\rho = 0.454 g/cm^3$

So here both have same density

so correct answer would be

Both objects are packed equally tightly.

6 0

3 years ago

Read 2 more answers

One afternoon, a couple walks three-fourths of the way around a circular lake, the radius of which is 2.51 km. they start at the

Marysya12 [62]

(a) Since the lake has a circular shape, the distance they traveled is exactly 3/4 of a circumference. The radius of the lake is 2.51 km, and the circumference is given by $2\pi r$ , therefore the distance covered is
$d= \frac{3}{4} (2 \pi r) = \frac{3}{2} \pi (2.51 km)=11.82 km$

(b) We can consider the lake to be on a xy-plane with the origin of the axes being at the center of the lake. In this system of coordinates, the starting point of the motion is at the west side of the lake, so at coordinates (-2.51 km,0). The final point is after 3/4 of circumference, therefore at the north side, at coordinates (0, 2.51 km).
So we can calculate the magnitude of the displacement as
$d= \sqrt{(x_f-x_i)^2+(y_f-y_i)^2} = \sqrt{(0-(-2.51))^2+(2.51-0)^2}=$
$=3.55 km$

(c) Considering only the initial and final point of the motion, the couple moved 2.51 km north (on the x-axis) and 2.51 km east (on the y-axis). Therefore, we can calculate the angle of the displacement with respect to the east direction:
$\tan \alpha = \frac{\Delta y}{\Delta x} = \frac{2.51 km}{2.51 km}=1$
from which
$\alpha=45^{\circ}$

3 0

3 years ago

How does the horizontal velocity of a projectile change throughout its motion?

Doss [256]

The force of gravity pulls vertically down on the object. It does not pull left or right, so there are no horizontal forces due to gravity. This means the horizontal velocity remains constant throughout the object's projectile parabolic path.

Note: this is assuming wind resistance is ignored. If you account for wind resistance, then the object will slow down because the air particles push against the object and impede its progress.

3 0

3 years ago

What does the formula "F=m xa" mean?

strojnjashka [21]

Answer:

Force = Mass x Acceleration

Explanation:

5 0

3 years ago