Question

If a brick of mass 2 kg falls from height of 10m what is its velocity when it s height is 5cm

Answer 1

GiveN :

• Mass of Brick (m) = 2kg
• Height from which brick falls (h) = 10 m

To Find :

• Velocity when height is 5 m

SolutioN :

Use 3rd equation of motion

$\dashrightarrow {\boxed{\tt{v^2 \: - \: u^2 \: = \: 2as}}} \\ \\ \dashrightarrow \tt{v^2 \: - \: 0^2 \: = \: 2 \: \times \: 9.8 \: \times \: 5} \\ \\ \dashrightarrow \tt{v^2 \: = \: 19.6 \: \times \: 5} \\ \\ \dashrightarrow \tt{v^2 \: = \: 98} \\ \\ \dashrightarrow \tt{v = \: \sqrt{98}} \\ \\ \dashrightarrow \tt{v \: = \: 9.9} \\ \\ \dashrightarrow \tt{v \: \approx \: 10} \\ \\ \underline{\sf{\therefore \: Velocity \: when \: height \: is \: 5m \: is \: 10 \: ms^{-1}}}$

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Additional information :

• Velocity is defined as rate of change of displacement.

• It's SI unit is m/s.

• It is a vector quantity.

• Velocity is denoted by “v or u”.

• v = s/t