F=-ks
F=-(390)(.45)
F=-175.5 N
Work=force x displacement
Work= 175.5(0.45)
Work= 78.98 J
Work = ∆E =78.98 J
Answer=79J (first option)
Answer:
About 7.67 m/s.
Explanation:
Mechanical energy is always conserved. Hence:

Where <em>U</em> is potential energy and <em>K</em> is kinetic energy.
Let the bottom of the slide be where potential energy equals zero. As a result, the final potential energy is zero. Additionally, because the child starts from rest, the initial kinetic energy is zero. Thus:

Substitute and solve for final velocity:

In conclusion, the child's speed at the bottom of the slide is about 7.67 m/s.
Answer:
a) System aceleration:
b) Direction of movement:
The block
down the plane when the acceleration is negative. This occur when:

The block
up the plane when the acceleration is positive. This occur when:

Explanation:
For the block
the move direction is parallel (||) to the plane
(1)
For the block
the move direction is vertical (y)
(2)
Both blocks are connected with the same cable, therefore, the tension on the cable and the acceleration is the same for both.
Solving the equation 2 for T:
(3)
replacing (3) in the equation (1)
(4)
solving (4) for a:

Answer:
I think 1 is d and 2 is A
Explanation:
but I may be wrong and I am so sorry if I am
The "blue" object would look the same. Say that this blue object is a square. That "square" is every color but blue. The only reason that you see it as "blue" is because what we call "blue", it the only color of light that bounces back at our eyes. Under all colors of light, especially simultaneously. This square or any shape for that matter would absorb the other colors of light, but the blue will be rejected. Therefore, we can only see what bounces back at our eyes, which is the color blue in this case.
Hope this helps, WyattMarine501