Answer:
W = F * s
Work done equals applied force * distance traveled
Apparent weight = M g (1 - sin θ) since some of applied force will lighten sled
μ = coefficient of kinetic friction
F cos θ = force applied to motion of sled
s = distance traveled
[μ M g (1 - sin θ)] cos θ * s = work done in moving sled
Note that F = μ M g if applied force is in the horizontal direction
Via half-life equation we have:

Where the initial amount is 50 grams, half-life is 4 minutes, and time elapsed is 12 minutes. By plugging those values in we get:

There is 6.25 grams left of Ra-229 after 12 minutes.
Answer:
The SI units of the “A” is m (meters)
The SI units of the “B” is m/s^2
Explanation:
Given the distance = d meters.
Time taken to travel = t (seconds)
Function of the distance, d = A + Bt^2
Now we have given the above information and from the given distance function, we have to find the SI units of the A and B. Here, below are the SI units.
Thus, the SI units of the “A” is = m (meters)
The SI units of the “B” is = m/s^2
Answer:
frictonal force due to the surface of irregularities