What are a few things that could not be used as evidence?
1 answer:
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Newton's second law states that the resultant of the forces applied to an object is equal to the product between the object's mass and its acceleration:
where in our problem, m is the mass the (child+cart) and a is the acceleration of the system.
We are only concerned about what it happens on the horizontal axis, so there are two forces acting on the cart+child system: the force F of the man pushing it, and the frictional force
acting in the opposite direction. So Newton's second law can be rewritten as
or
since the frictional force is 15 N and we want to achieve an acceleration of
, we can substitute these values to find what is the force the man needs:
where in our problem, m is the mass the (child+cart) and a is the acceleration of the system.
We are only concerned about what it happens on the horizontal axis, so there are two forces acting on the cart+child system: the force F of the man pushing it, and the frictional force
or
since the frictional force is 15 N and we want to achieve an acceleration of
Answer:
(a)
(b) 15 hours
Explanation:
half life, T = 12 hours
No = 19 g
(a) Let N be the amount remaining after time t.
Let λ be the decay constant.
The equation of radioactivity used here is given by
(b) N = 8 gram
Substitute the values in above equation
λ = 0.0577 per hour
So,
Take natural log on both the sides
- 0.0577 t = - 0.865
t = 15 hours