ANSWER:
250 J
STEP-BY-STEP EXPLANATION:
F = 20N is required to stretch the spring by 4 meters
We know that the force is equal to:

We solve for k (spring constant):

The work done in stretching the spring is given by the following equation (in this case the stretch is 10 meters:

The work required is 250 joules.
Answer:
1) ngle of incidence and reflection are equal, light carries does not change
2) the angle of this line with respect to the surface is 90º
3) protractor
4) n₂ sin θ₂ = n_1 sin θ₁, light ray must have a greater angle than the incident ray ,
Explanation:
1) When light falls on a reflective surface, the angle of incidence and reflection are equal and as it travels in the same medium, the speed that the light carries does not change
2) The normal is a line perpendicular to the point of incidence of light, so the angle of this line with respect to the surface is 90º
3) Angles are measured with a protractor
4) When light passes from one medium to another, the speed of the ray changes due to the difference in the refractive index in each medium, due to this change in speed the transmitted light ray must have a greater angle than the incident ray , since the speed increases as the density of the medium decreases
n₂ sin θ₂ = n_1 sin θ₁
Answer: i would say true uwu
Explanation:<u><em>hope this helps! </em></u>
<u><em> ....Max- </em></u>