Answer:
Work done, W = 0.0219 J
Explanation:
Given that,
Force constant of the spring, k = 290 N/m
Compression in the spring, x = 12.3 mm = 0.0123 m
We need to find the work done to compress a spring. The work done in this way is given by :


W = 0.0219 J
So, the work done by the spring is 0.0219 joules. Hence, this is the required solution.
Answer:
v = 7.67 m/s
Explanation:
Given data:
horizontal distance 11.98 m
Acceleration due to gravity 9.8 m/s^2
Assuming initial velocity is zero
we know that

solving for t
we have

substituing all value for time t

t = 1.56 s
we know that speed is given as


v = 7.67 m/s
Answer:
t = 4.41 10⁻⁴ years
Explanation:
For this exercise we must use the concept of average life time, which is the time in which the quantity and substance decays in half
= ln2 / λ
Let's calculate the decay constant of plutonium
λ = ln2 /
λ = ln 2 / 2.44 10⁵
λ = 2.84 10⁻⁶ s⁻¹
Radioactive decay is a first order process
N = No e (-λ t)
Where N is the number of nuclei, the mass is this by molecular weight
m = N PM
m / PM = m₀ / PM e (- λ t)
m / m₀ = e (- λ t)
-λ t = ln (m / m₀)
t = -1 /λ ln (m/m₀)
t = - 1 / 2.84 10⁻⁶ ln (0.1 / 0.35)
t = 4.41 10⁻⁴ years