Answer:
c. 12,500
Explanation:
Original number of atoms = 100,000 atoms
Half- life = 10min
Unknown:
The number of atoms that will remain after 10min = ?
Solution:
The half - life is the time taken for half of a radioactive substance to decay by half.
Time taken Number of atom half life
10min 100000 _
20min 50000 1
30min 25000 2
40min 12500 3
Answer:
Concrete
Explanation:
The speed at which sound propagates is medium dependent. As one of the forms of mechanical waves, sound requires a material medium for propagation from place to place.
- Sound travels with the least speed in air because air particles are far apart and they are randomized.
- Sound travels with the greatest speed in solids. Concrete is the only solid material given in the choice.
The speed of sound increases from air to liquid and to solid.
Answer:
x2 = 64 revolutions.
it rotate through 64 revolutions in the next 5.00 s
Explanation:
Given;
wheel rotates from rest with constant angular acceleration.
Initial angular speed v = 0
Time t = 2.50
Distance x = 8 rev
Applying equation of motion;
x = vt +0.5at^2 ........1
Since v = 0
x = 0.5at^2
making a the subject of formula;
a = x/0.5t^2 = 2x/t^2
a = angular acceleration
t = time taken
x = angular distance
Substituting the values;
a = 2(8)/2.5^2
a = 2.56 rev/s^2
velocity at t = 2.50
v1 = a×t = 2.56×2.50 = 6.4 rev/s
Through the next 5 second;
t2 = 5 seconds
a2 = 2.56 rev/s^2
v2 = 6.4 rev/s
From equation 1;
x = vt +0.5at^2
Substituting the values;
x2 = 6.4(5) + 0.5×2.56×5^2
x2 = 64 revolutions.
it rotate through 64 revolutions in the next 5.00 s
Answer:
m = 2218.67 kg
Explanation:
It is given that,
Initial velocity, u = 7.5 m/s
Final speed of an object, v = 0 (at rest)
Force, F = 5.2 kN
Time, t = 3.2 s
We need to find the mass of the object. Force acting on an object is given by :
F = ma
m is mass, a is acceleration
So, the mass of the object is 2218.67 kg
Answer:
2+ charge
Explanation: The alkaline earth metals have two valence electrons in their highest-energy orbitals (ns2). They are smaller than the alkali metals of the same period, and therefore have higher ionization energies. In most cases, the alkaline earth metals are ionized to form a 2+ charge
Hope this helps, have a great day :)
