Answer:
2632 foot-pound
Explanation:
Work done: Work is said to be done when ever a force moves a body through a given distance. The S.I unit of force is Newton (N).
From the question,
The expression for work done is given as,
W = Fdcos∅......................... Equation 1
Where W = work done, F = force, d = distance, ∅ = angle between the force and the horizontal.
Given: F = 32 lbs, d = 90 feet, ∅ = 24°
substitute into equation 1
W = 32×90×cos24
W = 2880(0.914)
W = 2632.32
W = 2632 foot-pound
solution:
We know v0 = 0, a = 9.8, t = 4.0. We need to solve for v
so,
we use the equation:
v = v0 + at
v = 0 + 9.8*4.0
v = 39.2 m/s
Now we just need to solve for d, so we use the equation:
d = v0t + 1/2*a*t^2
d = 0*4.0 + 1/2*9.8*4.0^2
d = 78.4 m
Answer:
200 million years
Explanation:
The equation that describes the decay of a radioactive isotope is
where
is the amount of radioactive isotope left at time t
is the initial amount of isotope
is the half-life of the sample
In this problem, the ratio between unstable isotope and daughter isotope is 1:15; this means that
Because the "total proportion" of original sample was 1+15=16.
Also we know that the half-life is
So we can re-arrange the equation to find t, the age of the rock:
So, 200 million years.
They help scientists explain concepts that are difficult to observe.
Answer:
Their atoms are spread farther apart
