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Motion in A Plane

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Physics Part I

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Physics

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CBSE Gujarat Board Haryana Board

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Class 10 Class 12
A projectile is fired with velocity u horizontally from height h. With what velocity will it strike the ground?

Consider a projectile being projected with velocity 'u' horizontally from height 'h'.

Let the projectile strike the ground with velocity 'v' after time t. 

              

Now, on resolving the components of velocity aong vertical and horizontal direction, we have 

straight u subscript straight x space equals space straight u space and space straight u subscript straight y equals 0
straight a subscript straight x space equals space 0 space and space straight a subscript straight y space equals space straight g space

Time taken by the body to reach the ground

We know that, 

space space space space space space space space space straight y space equals space straight y subscript straight o space plus space straight u subscript straight y straight t space plus space 1 half straight a subscript straight y straight t squared space
rightwards double arrow space space space space space straight h space equals space 0 plus 0 plus 1 half gt squared
rightwards double arrow space space space space space space straight t space equals space square root of fraction numerator 2 straight h over denominator straight g end fraction end root

Velocity of the body at ground

Let, vx and vy be the components of velocity along X-axis and Y-axis respectively. 

vx = ux + ax t = u 

vy = uy + ayt = gsquare root of fraction numerator 2 straight h over denominator straight g end fraction end root space equals square root of 2 g h end root

So, velocity, v = square root of straight v subscript straight x squared plus straight v subscript straight y squared end root space equals space square root of u squared plus 2 g h end root

tan space theta space equals space v subscript y over v subscript x space end subscript = fraction numerator square root of 2 gh end root over denominator straight u end fraction

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Give three examples of scalar quantities.

Mass, temperature and energy
769 Views

Give three examples of vector quantities.

Force, impulse and momentum.
865 Views

What is a vector quantity?

A physical quantity that requires direction along with magnitude, for its complete specification is called a vector quantity.
835 Views

What are the basic characteristics that a quantity must possess so that it may be a vector quantity?

A quantity must possess the direction and must follow the vector axioms. Any quantity that follows the vector axioms are classified as vectors. 


814 Views

What is a scalar quantity?

A physical quantity that requires only magnitude for its complete specification is called a scalar quantity.
1212 Views