# Vectors and Scalars

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#1
So the rule is that whenever you multiply a vector by a scalar you get a vector but KE = 1/2mv^2 and all energy is a scalar?
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2 years ago
#2
(Original post by G.Y)
So the rule is that whenever you multiply a vector by a scalar you get a vector but KE = 1/2mv^2 and all energy is a scalar?
Any scalar has magnitude only.
Vectors have magnitude and direction.

Multiplying a vector with a scalar changes the magnitude but not the direction.

Energy cannot be assigned a direction or a point of action. It s therefore a scalar.
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#3
(Original post by uberteknik)
Any scalar has magnitude only.
Vectors have magnitude and direction.

Multiplying a vector with a scalar changes the magnitude but not the direction.

Energy cannot be assigned a direction or a point of action. It s therefore a scalar.
You've just told me what I already know ://
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#4
Is KE an exception to the rule that multiplying a vector quantity by a scalar quantity gives you a vector quantity?
0
2 years ago
#5
(Original post by G.Y)
Is KE an exception to the rule that multiplying a vector quantity by a scalar quantity gives you a vector quantity?
Its still vector, you are technically saying the scalar force acting on the object is resolved in the direction of travel of the object you are talking about.
its like multiplying a positive by a negative, its still gonna be negative.
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2 years ago
#6
(Original post by G.Y)
Is KE an exception to the rule that multiplying a vector quantity by a scalar quantity gives you a vector quantity?
KE is NOT a vector.

The object in motion has a velocity vector. The energy of that object is a scalar.
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2 years ago
#7
(Original post by G.Y)
Is KE an exception to the rule that multiplying a vector quantity by a scalar quantity gives you a vector quantity?
It's a vector quantity with magnitude of the KE.
Energy is a scalar as it is the dot product of force and displacement.
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