How much heat is required to vaporize 1.5kg of liquid water at its boiling point
1 answer:
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Answer:
The speed decreases 75%.
Explanation:
- Since no friction present, assuming no external forces acting during the three collisions, total momentum must be conserved.
- For the first collission, only mass 1 is moving before it, so we can write the following equation:
- Since both masses are identical, and they stick together after the collision, we can express the final momentum as follows:
- From (1) and (2) we get:
- v₁ = v₀/2 (3)
- Since the masses are moving on a frictionless 1D track, the speed of the set of mass 1 and 2 combined together before colliding with mass 3 is just v₁, so the initial momentum prior the second collision (p₁) can be expressed as follows:
- Since after the collision the three masses stick together, we can express this final momentum (p₂) as follows:
- From (4) and (5) we get:
- v₂ = v₀/3 (6)
- Since the masses are moving on a frictionless 1D track, the speed of the set of mass 1, 2 and 3 combined together before colliding with mass 4 is just v₂, so the initial momentum prior the third collision (p₂) can be expressed as follows:
- Since after the collision the four masses stick together, we can express this final momentum (p₃) as follows:
- From (7) and (8) we get:
- v₃ = v₀/4
- This means that after the last collision, the speed will have been reduced to a 25% of the initial value, so it will have been reduced in a 75% regarding the initial value of v₀.
Answer:
134.77 mm
Explanation:
Wave length of light λ = 599 x 10⁻⁹ m
Slit separation d = 20 x 10⁻⁶ m
Screen distance D = 3 m
Distance of second dark fringe from centre
= 1.5 x λ D / d
Putting the values given above
distance =
= 134.77 x 10⁻³ m
= 134.77 mm.
Answer:
0.009 N, repulsive
Explanation:
The electrostatic force between two electric charges is given by:
where
k is the Coulomb's constant
q1 and q2 are the two charges
r is the separation between the two charges
In this problem, we have
are the two charges
r = 4.5 m is their separation
Substituting into the equation, we find
Moreover, the force is repulsive. In fact, the following rules apply:
- When two charges have same sign, they repel each other
- When two charges have opposite signs, they attract each other