Answer:
6 days.
Explanation:
From radioactivity, The expression for half life is given as,
R/R' = 2⁽ᵃ/ᵇ)................... Equation 1
Where R = original mass of the radioactive substance, R' = Remaining mass of the radioactive substance after decay, a = Total time taken to decay, b = half life.
Given: R = 80 g, R' = 10 g, b = 2 days.
Substitute into equation 1
80/10 = 2⁽ᵃ/²⁾
8 = 2⁽ᵃ/²⁾
2³ = 2⁽ᵃ/²)
Equating the base and solving for a
3 = a/2
a = 2×3
a = 6 days.
Answer:
Explanation:
PE = mgh = 60(9.8)(2.0) = 1176 J
The answer is A. Heat flows from high to low. For example, when you put an ice cube in a hot drink, the heat from the drink goes to the ice cube, and that is why it melts.
Y = +1-3 = -2
X = -5+7 = +2
D = √2^2-2^2 = 2√1+1 = 2√2 km
