Can velocity be positive with a negative displacement? Explain please :)

1 Answer
Mar 7, 2017

Answer:

Yes see explanation

Explanation:

There are two types of quantities, and it is important to know the difference;

1) Scalar quantities. These have magnitude ie. size only .
For example: temperature.

2) Vector quantities, these have BOTH size and direction.

to show the difference:

Consider an object moving North # 5ms^(-1)#

its speed is #5 ms^(-1)# and is a scalar

but its velocity of #5ms^(-1)# North is a vector.

Now distance is as scalar, but displacement is a vector

so if an object starts at the origin and moves# " "5 m" " # in the #+x-#axis then#" " 10 m " "#in the opposite direction, it ends up at#" " -5m " "#from the origin.

it has moved a distance of #" "15m" "#

but its displacement is #" "-5m." "#

if we use vector notation:

the object goes:#" "5veci-10veci=-5veci#

So displacement can be negative.

at this point the object can move with a velocity of, say, #" "2veci ms^(-1)#
so an object can have positive velocity and negative displacement

In fact the constant acceleration equations can be written into vector form, thus taking all of this into account.