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3 years ago

12

a ball is dropped from a height of 120 meters. If it takes 2.00 seconds for a ball to fall 60 meters, how long will it take the

ball to reach the ground?

1 answer:

Phantasy [73]3 years ago

5 0

It will take the ball 4 seconds to reach the ground because (120/2= 60/2=0= 2+2=4)

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the average american receives 2.28 mSv dose equivalent from radon each year. Assuming you receive this dose, and it all comes fr

Dmitry [639]

Answer:

The approximate number of decays this represent is $N= 23*10^{10}$

Explanation:

From the question we are told that

The amount of Radiation received by an average american is $I_a = 2.28 \ mSv$

The source of the radiation is $S = 5.49 MeV \ alpha \ particle$

Generally

$1 \ J/kg = 1000 mSv$

Therefore $2.28 \ mSv = \frac{2.28}{1000} = 2.28 *10^{-3} J/kg$

Also $1eV = 1.602 *10^{-19}J$

Therefore $2.28*10^{-3} \frac{J}{kg} = 2.28*10^{-3} \frac{J}{kg} * \frac{1ev}{1.602*10^{-19} J} = 1.43*10^{16} ev/kg$

An Average american weighs 88.7 kg

The total energy received is mathematically evaluated as

$1 kg ------> 1.423*10^{16}ev \\88.7kg --------> x$

Cross-multiplying and making x the subject

$x = 88.7 * 1.423*10^{16} eV$

$x = 126.2*10^{16}eV$

Therefore the total energy deposited is $x = 126.2*10^{16}eV$

The approximate number of decays this represent is mathematically evaluated as

N = $\frac{x}{S}$

Where n is the approximate number of decay

Substituting values

$N = \frac{126 .2*10^{16}}{5.49*10^6}$

$N= 23*10^{10}$

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3 years ago

10.A car is travelling at a constant speed of 27m/s. The driver looks away from the road for a 2.0s to tune in a station on the

Korvikt [17]

Explanation:

Distance = speed × time

d = (27 m/s) (2.0 s)

d = 54 m

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2 years ago

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Firlakuza [10]

As streams flow through Stone Mountain, layers of sand build up. Over time, the sand particles form a sedimentary rock called sandstone. What causes sandstone to change into metamorphic rock at Stone Mountain? Sandstone experiences intense heat and pressure.

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3 years ago

Read 2 more answers

If a particle's position is given by x=4-12t+3t^2, where t is in seconds and x is in meters, what is its velocity at t=1 second?

andreyandreev [35.5K]

Answer:

v = -6m/s

Explanation:

$x=4-12t+3t^2$

$\frac{dx}{dt}=-12+6t$

For t = 1:

$\frac{dx}{dt}=-6$

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3 years ago