Correct Answers is A.
The machines gives us some mechanical advantage. This means the mechanical average makes the work output greater than the work input
Simple most example is a lever. The force applied is smaller and the output work is larger as compared to input.
Option B cannot be true, as there must be a force to get some work done.
Option C and D are inverse of what a machine is designed for. A small force can be exerted through a large distance to have a large force exerted through a small distance. Common Example of this principle is a screw opener.
Light as a wave: Light can be described (modeled) as an electromagnetic wave. ... This changing magnetic field then creates a changing electric field and BOOM - you have light. Unlike many other waves (sound, water waves, waves in a football stadium), light does not need a medium to “wave” in.
Explanation:
Answer:
Explanation:
From A to B
distance traveled with velocity 
in time 
from B to C
distance traveled is 0.5 d with 
and 
velocity for half-half time
divide 1 and 2 we get
Now average velocity is given by
taking common
