Answer:
option A
Explanation:
A soccer field is about 100 meters of length, with the other instruments is possible to make the measure, but it will be very complex and it will take time. Therefore with the 50-m tape, the student will need only two measures.
Answer:

Explanation:
k = spring constant of the spring = 40 Nm⁻¹
A = amplitude of the simple harmonic motion = 4 cm = 0.04 m
m = mass of the block attached to spring = 0.20 kg
w = angular frequency of the simple harmonic motion
Angular frequency of the simple harmonic motion is given as 
= Speed of the block as it pass the equilibrium point
Speed of the block as it pass the equilibrium point is given as

Answer:
Electric field at a point ( x , y , z) is
.
Explanation:
Given :
Electric potential in the region is , 
We need to find the electric field .
We know , electric field ,
{ Here r is distance }
In coordinate system ,
{
is partial derivative }
Putting all values we get ,

Hence , this is the required solution.
The cornea is shaped like a dome and bends light to help the eye focus. Some of this light enters the eye through an opening called the pupil (PYOO-pul). The iris (the colored part of the eye) controls how much light the pupil lets in. Next, light passes through the lens (a clear inner part of the eye).
Answer:
Review each answer in the explanation part
Explanation:
Identify a problem or need = Aerospace engineers need a lightweight material to build a jet
Note: Identify a problem is related always with a need.
After identify the problem the next stage is the design
Design a solution = Engineers determine what features the material must have.
Note: The design process implies the choice of the materials and the proper numeric calculations.
Implement the solution = Engineers test a carbon - plastic compound in a wind tunnel.
Note: after the design, the following process is the built of the equipment and the different tests.
Evaluate the solution = The carbon-plastic compound is redesigned to save maximun energy.
Note: After testing, you enter a part of re-design that means making improvements to the already constructed.