## Filters

Q&A - Ask Doubts and Get Answers
Q

# Confused! kindly explain, A 30.0kg mass falls from a height of 4.0m. The momentum of the mass just before it hits the ground is

A 30.0 kg mass falls from a height of 4.0 m. The momentum of the mass just before it hits the ground  is

• Option 1)

144.2 kg m/s

• Option 2)

187.8 kg m/s.

• Option 3)

320.0 kg m/s.

• Option 4)

442.4 kg m/s.

134 Views

As discussed in

Perfectly Elastic Collision -

Law of conservation of momentum and that of Kinetic Energy hold good.

- wherein

$\frac{1}{2}m_{1}u_{1}^{2}+\frac{1}{2}m_{2}u_{2}^{2}= \frac{1}{2}m_{1}v_{1}^{2}+\frac{1}{2}m_{2}v_{2}^{2}$

$m_{1}u_{1}+m_{2}u_{2}=m_{1}v_{1}+m_{2}v_{2}$

$m_{1},m_{2}:masses$

$u_{1},v_{1}:initial \: and\: final \: velocity\: of \: the\: mass\ m_{1}$

$u_{2},v_{2}:initial \: and\: final \: velocity\: of \: the\: mass\ m_{2}$

$P=mv$

$v^{2}= u^{2}+2gh$        $u=0$

$v = \sqrt{2gh}\Rightarrow P = m\sqrt{2gh}$

$v= \sqrt{2\times 10\times 4} = 8.944 \:\: ms^{-1}$

$P=30\times 8.944=268.32 \:\: kg \:\: ms^{-1}$

Option 1)

144.2 kg m/s

This solution is incorrect

Option 2)

187.8 kg m/s.

This solution is incorrect

Option 3)

320.0 kg m/s.

This solution is incorrect

Option 4)

442.4 kg m/s.

This solution is incorrect

Exams
Articles
Questions