The eyes of many older people have lost the ability to accommodate, and so an older person’s near point may be more than 25 cm f
1 answer:
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Answer:
-58.8 J
Explanation:
The work done by a force is given by:
where
F is the magnitude of the force
d is the displacement of the object
is the angle between the direction of the force and the displacement.
In this problem, we are asked to find the work done by gravity, so we must calculate the magnitude of the force of gravity first, which is equal to the weight of the object:
The displacement of the object is d = 3.00 m, while , because the displacement is upward, while the force of gravity is downward; therefore, the work done by gravity is
And the work done is negative, because it is done against the motion of the object.
Decomposing the vector b on the x-axis and the y-axis, we get a rectangle triangle where the two sides are bx (x-axis) and by (y-axis), and b is the hypothenuse.
The component in x, bx, is equal to the product between the hypothenuse and the cosine of the angle between b and the x-axis, which is
:
The component in x, bx, is equal to the product between the hypothenuse and the cosine of the angle between b and the x-axis, which is
Answer:
The elastic potential energy is zero.
The net force acting on the spring is zero.
Explanation:
The equilibrium position of a spring is the position that the spring has when its neither compressed nor stretched - it is also called natural length of the spring.
Let's now analyze the different statements:
The spring constant is zero. --> false. The spring constant is never zero.
The elastic potential energy is at a maximum --> false. The elastic potential energy of a spring is given by
where k is the spring constant and x the displacement. Therefore, the elastic potential energy is maximum when x, the displacement, is maximum.
The elastic potential energy is zero. --> true. As we saw from the equation above, the elastic potential energy is zero when the displacement is zero (at the equilibrium position).
The displacement of the spring is at a maxi num --> false, for what we said above
The net force acting on the spring is zero. --> true, as the spring is neither compressed nor stretched