Iodine-131 has a half life of 8 days, so half of it is gone every 8 days.
10 grams of iodine-131 is left for 24 days.
At 8 days: 10/2=5 grams left
At 16 days: 5/2=2.5 grams left
At 24 days: 2.5/2=1.25 grams left.
**
Your mistake is that you stopped at 16 days.
Answer:
the kinetic energy lost due to friction is 22.5 J
Explanation:
Given;
mass of the block, m = 0.2 kg
initial velocity of the block, u = 25 m/s
final velocity of the block, v = 20 m/s
The kinetic energy lost due to friction is calculated as;
Therefore, the kinetic energy lost due to friction is 22.5 J
Answer:
Positive velocity and negative acceleration
Explanation:
An object moving in the positive direction has a positive velocity.
An object that's slowing down while moving in the positive direction has a negative acceleration.
<span>To find the wavelength of a neutron can be calculated by using the formula
Wavelength=h/m x v
Where h is planck's constant
m=mass of neutron
v= velocity of the particle
By substituting the given values
Wavelength= 6.63 × 10–34 j s / 1.675 × 10–27 kg x 2 m/s^-1
Wavelength of a neutron=1.979 x 10^-7 m</span>
