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2 years ago

If two objects collide and are stationary, what must the total momentum of the sum of the objects have been before collision?

Physics

1 answer:

s344n2d4d5 [400]2 years ago

8 0

Explanation:

Concept: In collision between two isolated bodies momentum is always conserved.

Also, if the collision is elastic kinetic energies are also conserved

m1v1i + m2v2i = m1v1f + m2v2f.

and in elastic collision

$½m1v1i^2 + ½m2v2i^2 = ½m1v1f^2 + ½m2v2f^2.$

Momentum is preserved in collisions between two objects. The initial moment not being zero, the final momentum is not zero. This means both object has to be in motion.

However, it may be possible for one of the objects to be at rest after the collision. For instance, if the masses of the two objects are same, then after a head-on elastic collision the object initially at rest is moving and the object initially moving is at rest.

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Is a vector necessarily changed if it is rotated through an angle ?Explain

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Yes, since it depends on the normal and resultant

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3 years ago

HELP PLS i need this right now

N76 [4]

Answer:

V = 44.4 units.

Explanation:

In order to solve this problem, we must use the Pythagorean theorem. Which is defined by the following expression.

$V = \sqrt{(V_{x})^{2} +(V_{y})^{2} }$

where:

Vx = - 43 units

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$V=\sqrt{(-43)^{2} +(11.1)^{2} }\\V=44.4 units$

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3 years ago

To boil water it requires heat , what happens to the heat when the water cools down as energy can neither be destroyed nor be cr

skelet666 [1.2K]

Answer:

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3 years ago

Read 2 more answers

Two resistors are to be combined in parallelto form an equivalent resistance of 400Ω. The resistors are takenfrom available stoc

vivado [14]

Answer:

Δ $R_{e}$ = 84 Ω, $R_{e}$ = (40 ± 8) 10¹ Ω

Explanation:

The formula for parallel equivalent resistance is

1 / $R_{e}$ = ∑ 1 / Ri

In our case we use a resistance of each

R₁ = 500 ± 50 Ω

R₂ = 2000 ± 5%

This percentage equals

0.05 = ΔR₂ / R₂

ΔR₂ = 0.05 R₂

ΔR₂ = 0.05 2000 = 100 Ω

We write the resistance

R₂ = 2000 ± 100 Ω

We apply the initial formula

1 / $R_{e}$ = 1 / R₁ + 1 / R₂

1 / $R_{e}$ = 1/500 + 1/2000 = 0.0025

$R_{e}$ = 400 Ω

Let's look for the error (uncertainly) of Re

$R_{e}$ = R₁R₂ / (R₁ + R₂)

R’= R₁ + R₂

$R_{e}$ = R₁R₂ / R’

Let's look for the uncertainty of this equation

Δ $R_{e}$ / $R_{e}$ = ΔR₁ / R₁ + ΔR₂ / R₂ + ΔR’/ R’

The uncertainty of a sum is

ΔR’= ΔR₁ + ΔR₂

We substitute the values

Δ $R_{e}$ / 400 = 50/500 + 100/2000 + (50 +100) / (500 + 2000)

Δ $R_{e}$ / 400 = 0.1 + 0.05 + 0.06

Δ $R_{e}$ = 0.21 400

Δ $R_{e}$ = 84 Ω

Let's write the resistance value with the correct significant figures

$R_{e}$ = (40 ± 8) 10¹ Ω

6 0

3 years ago

A fishing boat accidentally spills 3.0 barrels of diesel oil into the ocean. each barrel contains 42 gallons. if the oil film on

9966 [12]

Number of barrels are 3.0. Each barrel contains 42 gallons of oil. Thus, total volume of oil will be 42×3=126 gallons.

Converting gallons into m^{3}

1 gallon=0.00378 m^{3}

Thus, 126 gallons=0.4769 m^{3}

Thickness of oil film is 2.5\times 10^{2} nm, converting it into meters as follows:

1 nm=10^{-9} m

Thus,

2.5\times 10^{2} nm=1.5\times 10^{-7}m

Now, volume V of oil is related to area A and thickness T as follows:

V=A×T

rearranging,

A=\frac{V}{T}=\frac{0.4769 m^{3}}{2\times 10^{-7}m}=2.38\times 10^{6}m^{2}

Thus, square meters of oil will be 2.38\times 10^{6}m^{2}

7 0

3 years ago