A. molecules are CONSTANTLY moving.
Answer: 
Explanation:
Given
Length of the race track 
the radius of curvature of the track 
time taken to run on track is 
Speed of runner is

Centripetal acceleration is

Explanation:
Spring is stretched by force f to distance
"X"
now here by force balance we can say
f = kx
k = !
now here we will we say that energy stored in the spring will convert into kinetic energy
kx² = mv²
(x² = mv²
now solving above equation we will have
PART 2)
now for half of the extension again we can use energy conservation
ka²-k(x/2)² = 1 {mv²
¾fx=mv²
now the speed is given as
3 fr 4m V=
Answer and Explanation:
with reference to Einstein's theory of special relativity, the speed of an electromagnetic radiation, here, laser will not change in any inertial frame or remains same irrespective of any change in inertial frame.
Therefore, the speed of light measured in both the cases, i.e., in astronaut's reference frame and spaceship's reference frame will be equal to the speed of light in vacuum, i.e.,
.
The laser gun's speed in astronaut's reference frame is the same as the speed of the spaceship as it mounted on it, i.e., the speed of the laser gun is 200 million m/s.
The laser gun's speed measured in spaceship's reference frame will be zero, as it is mounted on the spaceship and is stationary in the spaceship's reference frame.
I am pretty sure that<span> the following which describes resistance force is the fourth option from the scale represented above : </span>D .force applied by the machine to overcome resistance. I choose this due to the Newton's 3rd law, as the<span> force that shoul be overcome by a machine before it perform its usual work. Do hope you will find it helpful! Regards!</span>