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4 years ago

Choose the enternative

Physics

1 answer:

Fofino [41]4 years ago

5 0

10, 20, 40 cannot be made to equal zero.

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The half-life of plutonium 239 is 24,200 years. Assume that the decay rate is proportional to the amount. Determine the amount o

kotykmax [81]

Answer:

time taken is equal to 14,156 years

Explanation:

we know,

$Y=Ae^{-kt}$

at t = 0

Y(0) = A

given that half life of plutonium 239 = 24,200

$\dfrac{A}{2}=Ae^{-kt}\\0.5=e^{-kt}\\k\times 24200 = ln(2)\\k = \dfrac{ ln(2)}{24200}$

$Y=Ae^{-kt}$

$\frac{3}{2} = e^{-kt}\\ln(1.5)=-\dfrac{ ln(2)}{24200}\times t\\t=-\dfrac{ln(1.5)\times 24200}{ ln(2)}\\t=14,156 \ years$

hence time taken is equal to 14,156 years

5 0

3 years ago

Sledding down a hill, you are traveling at 10 m/s when you reach the bottom. You (inertia 80 kg ) then move across horizontal sn

RSB [31]

Answer:

V = 0.32 m /s

Explanation:

Momentum of the man on the sledge along with sledge

= (80+8) x 10 = 880 kg. m/s When the man jumps off the sledge , the velocity of the sledge will remain intact at 10 m/s

When the sledge hits the boulder and bounces back the momentum of the sledge - boulder system will remain conserved .

change in momentum of sledge = 8 x (10 +6 )

= 128 kg m/s

Change in the momentum of boulder

= 400 V -0

= 400V

400V = 128

V = 0.32 m /s

5 0

3 years ago

Suppose a 65 kg person stands at the edge of a 6.5 m diameter merry-go-round turntable that is mounted on frictionless bearings

Hatshy [7]

Answer:0.316 rad/s

Explanation:

Given

mass of Person $m=65 kg$

velocity of person $v=3.8 m/s$

diameter of turntable $d=6.5 m$

moment of Inertia of the table $I_0=1850 kg-m^2$

Moment of inertia of Person I

$I=mr^2=65\times (\frac{6.5}{2})^2$

$I=686.56 kg-m^2$

initial angular velocity $\omega _1=\frac{v}{r}$

$\omega _1=\frac{3.8}{3.25}=1.17 rad/s$

Conserving Angular momentum

$I\omega _1=(I+I_0)\omega _2$ , where $\omega _2=final\ angular\ velocity$

$686.56\times 1.17=(686.56+1850)\times \omega _2$

$\omega _2=\frac{686.56}{2536.56}\times 1.17$

$\omega _2=0.316 rad/s$

4 0

3 years ago

A 60-watt light bulb has a voltage of 120 bolts applied across it and a current of 0.5 amperes flows through the bulb. What is t

Andre45 [30]

Answer:

240 ohms

Explanation:

From Ohms law we deduce that V=IR and making R the subject of the formula then R=V/I where R is resistance, I is current and V is coltage across. Substituting 120 V for V and 0.5 A for A then

R=120/0.5=240 Ohms

Alternatively, resistance is equal to voltage squared divided by watts hence $\frac {120^{2}}{60}=240$

7 0

4 years ago

Why is carrying for the earth necessary? explain

monitta

Answer: We will survive

Explanation: Caring for the earth is something that we need to do to live or survive on earth because if we don't we may not survive.

Hope this helps! :)

6 0

3 years ago

Read 2 more answers