Its tangential speed is constant although its velocity is changing. As the object changes direction, it results in a changing of positive and negative signs of the velocity. Although, the magnitude of the velocity (speed) is not changing.
Answer:
The train's displacement is zero.
Explanation:
Given data,
The time taken by the train from NY to Washington and back is, t = 6 h 5 min
The distance between the two stations is, d = 363 km
Therefore, the total distance the train traveled is, d' = 726 km
The displacement is defined as the change in position coordinates with respect to its original position.
If the train travels from one point and returns back to the same point after some time, there is no change in the position coordinates with respect to its original position.
Hence, the train's displacement is zero.
It is a chemical change. I always think of a chemical/physical change as if you could reverse it back as it started off, for example if you stepped on a can you can reverse the can back probably not exactly like it was before but you can still reverse it so this would be a physical change, and if you baked a pizza you could not reverse the dough and everything else back.
Answer:

The formula for escape velocity where:
G - Gravitational constant (9.81 etc.)
M - the mass of the object the escape should be made from
r - distance to the centre of that mass
The answer is A) velocity, because velocity is speed and displacement.
Hope this helps