Question

An object of mass 1.5kg travelling in a straight line with a velocity of 5m/s collides with a wooden block of mass 5kg resting on the floor. This object sticks with the wooden block after collision and both move together in a straight line. Calculate:
(a)the total momentum before collision.
(b) total momentum after collision
(c) the velocity of the combination of these objects after collision

PLEASE FAST VERY URGENT

Answer 1

Answer:

This is your required answer.

Answer 2

☘ Required Answer ☘

a ) the total momentum before collision.

We'll firstly find the momentum of the object and momentum of the wooden block and then we'll add both to find total momentum before collision.

• Momentum of the object = mass of the object × velocity of the object

➨ Mass of the object = 1.5 kg [ Given ]

➨ Velocity of the object = 5 m/s [ Given ]

➜ Momentum of the object = 1.5 × 5

⠀ ⠀ ⠀ ⠀ ⠀⠀ ⠀ ⠀ ⠀ ⠀ ⠀⠀⠀ = 7.5kg m/s

• Momentum of the wooden block = mass of the wooden block × velocity of the wooden block

➨ Mass of the wooden block = 5 kg [ Given ]

➨ Velocity of the object = 0 m/s ( since it is at rest ) [ Given ]

➜ Momentum of the object = 5 × 0

⠀ ⠀ ⠀ ⠀ ⠀⠀ ⠀ ⠀ ⠀ ⠀ ⠀⠀⠀ = 0kg m/s

Total momentum of object and wooden block ( before collision ) = 7.5 + 0

⠀ ⠀ ⠀ ⠀ ⠀⠀ ⠀ ⠀ = 7.5 kg m/s

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b ) Total momentum after collision.

The total momentum will remain constant because there no external force is applied. According to the law of conservation of momentum when two bodies are acting upon each other, their total momentum will remain constant or conserved if no external force is acting.

Therefore, total momentum after collision will be 7.5 kg m/s as there is no external force applied.

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c ) the velocity of the combination of these objects after collision

Now according to the law of conservation of mass:

• $\sf { m_1v_1 + m_2v_2 = ( m_1 + m_2 )v }$

[ v is here combined velocity ]

$\sf { ➨ 1.5 \times 5 + 5 \times 0 = ( 1.5 + 5 )v }$

$\sf { ➨ 7.5 + 0 = 6.5v }$

$\sf { ➨ 7.5 = 6.5v }$

$\sf { ➨ v = \dfrac{7.5}{6.5}}$

$\sf { ➨ v = 1.15 m/s }$

Therefore, the velocity of the combination of these objects after collision will be 1.15 m/s.

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