# Tag Info

Accepted

### How do I know if a motion is 1 dimensional or 2 dimensional?

Let's say you have the following motion (the red arrow) It looks 2D on this plot, since its motion changes both the $x$- and $y$-coordinates. However, if you redefine the axes like so: Then the ...
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### How do I know if a motion is 1 dimensional or 2 dimensional?

Both you and your teacher can be correct depending on what you mean by "dimension." In everyday experience, we generally consider dimensionality to be the number of independent parameters ...
• 504

### What does it mean when vector quantity is negative?

$-\vec v$ is a vector which has the same magnitude as $\vec v$ but points in the opposite direction. So $\vec v + (-\vec v)=0$.
• 103k

• 12.4k
Accepted

### Is the answer given in the option wrong?

The answer sheet is correct. You are ignoring the statement “The direction of the motion of the object changed only once, at time t.” That means that the velocity was zero at time t. So before time t ...
• 103k