Note that
1 m = 3.2808 ft

Therefore
1 km = 3280.8 ft
and
$32.56 \, \frac{km}{h} = (32.56 \, \frac{km}{h})*(3280.8 \, \frac{ft}{km}) = 1.0682 \, \times 10^{5} \, \frac{ft}{h}$

Answer: 1.0682 x 10⁵ ft/hr

8 0

2 years ago

One of the radioactive isotopes used in medical treatment or analysis is chromium-51. The half-life of chromium-51 is 28 days. H

Goryan [66]

Answer : The time required for decay is, 84 days.

Explanation :

Half-life of chromium-51 = 28 days

First we have to calculate the rate constant, we use the formula :

$k=\frac{0.693}{t_{1/2}}$

$k=\frac{0.693}{28\text{ days}}$

$k=0.0248\text{ days}^{-1}$

Now we have to calculate the time required for decay.

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant

t = time taken by sample = ?

a = let initial activity of the sample = 100

a - x = amount left after decay process = 12.5

Now put all the given values in above equation, we get

$t=\frac{2.303}{0.0248}\log\frac{100}{12.5}$

$t=83.9\text{ days}\approx 84\text{ days}$

Therefore, the time required for decay is, 84 days.

7 0

3 years ago

What experimental evidence was provided for the nuclear model of an atom

UkoKoshka [18]

Alpha particles bouncing off of gold foil.

6 0

3 years ago

Assuming all volume measurements are made at the same temperature and pressure, how many liters of oxygen gas would it take to r

EleoNora [17]

2H2 (g) + O2 (g) -->2H2 O(g)
mole ratio of H2:O2=2:1
7.25/2=3.625

3 0

3 years ago