Answer:
D
Explanation:
I just took the test and C was wrong, do not listen to that answer. It is "All of the above"
Answer:
Option A
Explanation:
Velocity is expressed as distance covered per unit time, with respect to direction. Therefore, v=d/t
Given distance west as 60 km and time as 1.33 then velocity will be
V=60/1.33=45.112781954887 km/h
Rounded off as 45.11 km/h West
Velocity in East will also be given by substituting 40 km for d and 0.67 h for h hence
V=40/0.67=59.701492537313 km/h rounded off as 59.70 km/h East
Taking East as positive then West as negative, the sum of two velocities will be (59.70+-45.11)/2=7.295 km/h East
Approximately 10 km/h East since it is positive
They have 6 faces
12 edges
8 edges
Answer:
1280 mg
Explanation:
Radioactive decay is a phenomenon that occurs when a certain isotope of an element, said to be radioactive, decays, turning into a lighter nucleus and emitting radiation + energy in the process.
The radioactive decay of this isotope of polonium is described by the equation
where
is the amount of polonium left after time t
is the amount of polonium t time t = 0
is the half-life of the polonium, in days (it is the time it takes for the initial element to halve its amount)
IN this problem, we know that:
After t = 560 days, the amount of polonium left is 
. Therefore, we can re-arrange the equation, substituting t = 560 d, and solve for to find the initial amount of polonium:
