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2 years ago

How is it possible for two objects to have the same momentum, but different velocities?

1 answer:

8 0

Answer: momentum has the same direction as that of velocity but when 2 bodies with the same linear momentum & different velocities it has different masses because a vector quantity is represented by a cross product of mass and velocity of object .

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Two point charges, with charge magnitudes q and ????, are placed a distance r apart. In this arrangement, each point charge expe

sammy [17]

Answer:

1) Q ’= 8 Q , 2) q ’= 16 q , 3) r ’= ¾ r

Explanation:

For this exercise we will use Coulomb's law

F = k q Q / r²

It asks us to calculate the change of any of the parameters so that the force is always F

Original values

q, Q, r

Scenario 1

q ’= 2q

r ’= 4r

F = k q ’Q’ / r’²

we substitute

F = k 2q Q ’/ (4r)²

F = k 2q Q '/ 16r²

we substitute the value of F

k q Q / r² = k q Q '/ 8r²

Q ’= 8 Q

Scenario 2

Q ’= Q

r ’= 4r

we substitute

F = k q ’Q / 16r²

k q Q / r² = k q’ Q / 16 r²

q ’= 16 q

Scenario 3

q ’= 3/2 q

Q ’= ⅜ Q

we substitute

k q Q r² = k (3/2 q) (⅜ Q) / r’²

r’² = 9/16 r²

r ’= ¾ r

6 0

3 years ago

A submarine is stranded on the bottom of the ocean with its hatch 21.0 m below the surface. calculate the force (in n) needed to

Tanzania [10]

Answer:

28,400 N

Explanation:

Let's start by calculating the pressure that acts on the upper surface of the hatch. It is given by the sum of the atmospheric pressure and the pressure due to the columb of water, which is given by Stevin's law:

$p_{top} = p_{atm} + \rho g h=1.013\cdot 10^5 Pa + (1000 kg/m^3)(9.8 m/s^2)(21.0 m)=3.071 \cdot 10^5 Pa$

On the lower part of the hatch, there is a pressure equal to

$p_{bot}=p_{atm}=1.013\cdot 10^5 Pa$

So, the net pressure acting on the hatch is

$p=p_{top}-p_{bot}=3.071 \cdot 10^5 Pa - 1.013\cdot 10^5 Pa=2.058 \cdot 10^5 Pa$

which acts from above.

The area of the hatch is given by:

$A=\pi r^2 = \pi (\frac{0.420 m}{2})^2=0.138 m^2$

So, the force needed to open the hatch from the inside is equal to the pressure multiplied by the area of the hatch:

$F=pA=(2.058\cdot 10^5 Pa)(0.138 m^2)=28,400 N$

8 0

3 years ago

A diver 40 m deep in 10 degrees C fresh water exhales a 1.5 cm diameter bubble.

zzz [600]

Answer:

0.0257259766982 m

Explanation:

$P_2$ = Atmospheric pressure = 101325 Pa

$d_1$ = Initial diameter = 1.5 cm

$d_2$ = Final diameter

$\rho$ = Density of water = 1000 kg/m³

h = Depth = 40 m

The pressure is

$P_1=P_2+\rho gh\\\Rightarrow P_1=101325+1000\times 9.81\times 40\\\Rightarrow P_1=493725\ Pa$

From ideal gas law we have

$\dfrac{P_1V_1}{T_1}=\dfrac{P_2V_2}{T_2}\\\Rightarrow \dfrac{P_1\dfrac{4}{3\times8}\pi d_1^3}{T_1}=\dfrac{P_2\dfrac{4}{3\times8}\pi d_2^3}{T_2}\\\Rightarrow \dfrac{P_1d_1^3}{T_1}=\dfrac{P_2d_2^3}{T_2}\\\Rightarrow d_2=(\dfrac{P_1d_1^3T_2}{P_2T_1})^{\dfrac{1}{3}}\\\Rightarrow d_2=(\dfrac{493725\times 0.015^3\times (20+273.15)}{101325\times (10+273.15)})^{\dfrac{1}{3}}\\\Rightarrow d_2=0.0257259766982\ m$