In a chemical reaction, the bonds in the molecules
2 answers:
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Answer:
.
Explanation:
By Newton's Second Law, the acceleration of an object is proportional to the net force
on it. In particular, if the mass of the object is
, then
.
Rewrite this equation to obtain:
.
In this case, the assumption is that the force is the only force that is acting on the object. Hence, the net force
on the object would also be
Make sure that all values are in their standard units. Forces should be in Newtons (same as , and the acceleration of the object should be in meters-per-second-squared (
). Apply the equation
to find the mass of the object.
.
Answer:
v= 4.0 m/s
Explanation:
- When standing on the bathroom scale within the moving elevator, there are two forces acting on Henry's mass: Normal force and gravity.
- Gravity is always downward, and normal force is perpendicular to the surface on which the mass is located (the bathroom scale), in upward direction.
- Normal force, can adopt any value needed to match the acceleration of the mass, according to Newton's 2nd Law.
- Gravity (which we call weight near the Earth's surface) can be calculated as follows:
- According to Newton's 2nd Law, it must be met the following condition:
- As the gravity is larger than normal force, this means that the acceleration is downward, so, we choose this direction as the positive.
- Solving for a, we get:
- We can find the speed after the first 3.8 s (assuming a is constant), applying the definition of acceleration as the rate of change of velocity:
- Now, if during the next 3.8 s, normal force is 930 N (same as the weight), this means that both forces are equal each other, so net force is 0.
- According to Newton's 2nd Law, if net force is 0, the object is either or at rest, or moving at a constant speed.
- As the elevator was moving, the only choice is that it is moving at a constant speed, the same that it had when the scale was read for the first time, i.e., 4 m/s downward.