Prior to determining the
experimental design, a scientist typically forms a hypothesis. The answer is
letter B. this is to prepare the scientist, the possible outcome of their
research before the experimental design whether they are wrong or not.
A. the medium through which the light travels changes.
Explanation:
Light waves will continue to travel in a straight line in all directions from their source unless the medium through which the light travels changes.
A change in medium causes light to exhibit different properties. Also, when light hits an obstacle, they can be diffracted.
- The way light travels on crossing a boundary differs.
- At the boundary between two medium, light can either be reflected back or refracted when they cross the medium
- This will cause the light rays to bend towards or away from the normal depending on the properties of the medium.
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Observer A is moving inside the train
so here observer A will not be able to see the change in position of train as he is standing in the same reference frame
So here as per observer A the train will remain at rest and its not moving at all
Observer B is standing on the platform so here it is a stationary reference frame which is outside the moving body
So here observer B will see the actual motion of train which is moving in forward direction away from the platform
Observer C is inside other train which is moving in opposite direction on parallel track. So as per observer C the train is coming nearer to him at faster speed then the actual speed because they are moving in opposite direction
So the distance between them will decrease at faster rate
Now as per Newton's II law
F = ma
Now if train apply the brakes the net force on it will be opposite to its motion
So we can say
- F = ma

so here acceleration negative will show that train will get slower and its distance with respect to us is now increasing with less rate
It is not affected by the gravity because the gravity will cause the weight of train and this weight is always counterbalanced by normal force on the train
So there is no effect on train motion
Answer: B. 15.2s
Explanation: 600/39.5 = about 15.2
Answer:
in the direction of motion of Jacob
Explanation:
Given:
mass of Jacob, 
velocity of Jacob, 
mass of Ethan, 
velocity of Ethan, 
Now using the conservation of linear momentum for the case:
(When the two masses in motion combine to form one after the collision then they will move together in the direction of the greater momentum.)


in the direction of motion of Jacob as it was assumed to be positive.