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3 years ago

Answer the question below:

Physics

2 answers:

OLga [1]3 years ago

8 0

Answer:

Its D

Explanation:

Bezzdna [24]3 years ago

6 0

Answer:

D) the decay rates of radioactive uranium and lead

Explanation:

As we know that when she found the substance it must have some fixed ratio of radioactive uranium and Lead in that substance.

Here since Uranium is radioactive substance so it will continuously convert into Lead and this ratio will change with time

So here we can say that the ratio of radioactive uranium and lead will depend on its decay rate

now to find the age of the substance we can find the present ratio of lead and uranium in that substance and then compare it with freshly prepared substance.

so by the formula

we can find the age of the sample

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Calculate the volume of the metal required to make a hemisperical bowl with internal and external radii 8.4cm and 9.1cm respecti

ioda

External = R
Internal = r
Volume of hemisperical = 2/3 π(R³-r³)
V= 2/3 π(9.1³ - 8.4³)
V= 336.9 cm³

4 0

3 years ago

A steel ball bearing is released from a height H and

ArbitrLikvidat [17]

Answer:

ELASTIC collision

kinetic energy is conservate

Explanation:

As the ball bounces to the same height, it can be stated that the impact with the floor is ELASTIC.

As the floor does not move the conservation of the moment

po = pf

-mv1 = m v2

- v1 = v2

So the speed with which it descends is equal to the speed with which it rises

Therefore the kinetic energy of the ball before and after the collision is the same

4 0

3 years ago

6. A satellite is orbiting Earth just above its surface. The centripetal force making the satellite follow a circular trajectory

Svetllana [295]

Answer:

Engular velocity: $w=1,24*10^{-3}/s$

Linear velocity: $V=7905 m/s$

The time it takes:

$t=5060s=84min$

Explanation:

The magnitude of the centripetal acceleration can be related to the angular velocity and radius as:

(1) $a=r*w^{2}$

Solving for w:

(2) $w=\sqrt{\frac{a}{r} }$

Replacing a=9,8m/s2 and r=6,375,000m:

(3) $w=\sqrt{\frac{9,8m/s^{2}}{6375000m} }=1,24*10^{-3}/s$

And the angular velocity relates to the linear velocity:

$V=w*r=1,24*10^{-3}/s*6375000m=7905 m/s$

The perimeter of the orbit is:

$P=\pi *2*r=\pi *2*6375000m=40.05*10^{6}m$

The time it takes:

$t=\frac{P}{V} =\frac{40.05*10^{6}m}{7905 m/s}=5060s=84min$

5 0

3 years ago

If the area of an iron rod is 10 cm by 0.5 cm and length is 35 cm. Find the value of resistance, if 11x10^-8 ohm.m be the resist

malfutka [58]

Answer:

Resistance of the iron rod, R = 0.000077 ohms

Explanation:

It is given that,

Area of iron rod, $A=10\ cm\times 0.5\ cm=5\ cm^2 = 0.0005\ m^2$

Length of the rod, L = 35 cm = 0.35 m

Resistivity of Iron, $\rho=11\times 10^{-8}\ \Omega-m$

We need to find the resistance of the iron rod. It is given by :

$R=\rho\dfrac{L}{A}$

$R=11\times 10^{-8}\times \dfrac{0.35\ m}{0.0005\ m^2}$

$R=0.000077 \Omega$

So, the resistance of the rod is 0.000077 ohms. Hence, this is the required solution.

6 0

3 years ago

The four-firm concentration ratio for newstands is 17 and for electric lamp makers it is 89. The HHI for newstands is 105 and f

TEA [102]

Answer:

is; is not

Explanation:

The four-firm concentration ratio for newstands is 17 and for electric lamp makers it is 89. The HHI for newstands is 105 and for electric lamp makers it is 2 comma 850. The newstand market is an example of monopolistic competition. The electric lamp market is not an example of monopolistic competition

4 0

3 years ago