It's false. Mass is a way of measuring how much matter an object contains, where as weight measures how hard gravity is pulling on an object. While on earth, these are typically interchangeable. However, if you were to go to Mars, your mass would stay the same, but the weight will be different. This is because you still contain the same amount of matter, but the gravity's pull will be different because the moon has a different gravitational pull than the earth. Hope this helps!
B. surface wave because it is a mechanical energy
Answer:
Approximately 
.
Explanation:
<h3>Solve this question with a speed-time plot</h3>
The skateboarder started with an initial speed of 
and came to a stop when her speed became 
. How much time would that take if her acceleration is 
?
.
Refer to the speed-time graph in the diagram attached. This diagram shows the velocity-time plot of this skateboarder between the time she reached the incline and the time when she came to a stop. This plot, along with the vertical speed axis and the horizontal time axis, form a triangle. The area of this triangle should be equal to the distance that the skateboarder travelled while she was moving up this incline until she came to a stop. For this particular question, that area is approximately equal to:
.
In other words, the skateboarder travelled 
up the slope until she came to a stop.
<h3>Solve this question with an SUVAT equation</h3>
A more general equation for this kind of motion is:
,
where:
and 
are the initial and final velocity of the object,
is the constant acceleration that changed the velocity of this object from to , and
is the distance that this object travelled while its velocity changed from to .
For the skateboarder in this question:
.
Answer:
The diaphragm.
Explanation:
A diaphragm is a thin non transparent structure with an aperture at its center. Aperture is the opening in a lens through which light passes to enter the camera. Diaphragm controls the passage of light through specimen. It stops the passage of light except for the light passing through aperture. It also limits the brightness of light reaching the focal plane.
The diaphragm is placed close to the lens, where objects are defocused to the maximum in order to pass every ray from the object through the lens. Diaphragm discards some of those rays but allows multiple rays to move through to produce an image. This means that the size of the aperture controls the amount of light that passes through the lens. The center of the aperture coincides with optical axis of the lens. Iris diaphragm is an example. It is used in modern cameras.
