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3 years ago

Which material is colder in a room where all the objects are in for a long time?

Physics

1 answer:

Ahat [919]3 years ago

3 0

Wooden desk it doesn’t conduct or absorb heat as much as metal or plastic

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Are the two expressions equvalent 7(8x+5) and 48x + 35

Evgesh-ka [11]

Yes they are equivalent because 7x5=35 and 8x x 5=48x

4 0

4 years ago

Calculate the electric force an electron exerts upon a proton inside a He atom if they are d=2.7⋅10^-10m apart.

maksim [4K]

Explanation:

Charge of electron in He, $q_e=1.6\times 10^{-19}\ kg$

Charge of proton in He, $q_p=1.6\times 10^{-19}\ kg$

Distance between them, $d=2.7\times 10^{-10}\ m$

We need to find the electric force between them. It is given by :

$F=k\dfrac{q_eq_p}{d^2}$

$F=-9\times 10^9\times \dfrac{(1.6\times 10^{-19}\ C)^2}{(2.7\times 10^{-10}\ m)^2}$

$F=-3.16\times 10^{-9}\ N$

Since, there are two protons so, the force become double i.e.

$F=2\times 3.16\times 10^{-9}\ N$

$F=6.32\times 10^{-9}\ N$

So, the correct option is (c). Hence, this is the required solution.

6 0

3 years ago

ASAP

nikitadnepr [17]

Answer:

A. 59.4

Explanation:

The refractive index of the glass, n₁ = 1.50

The angle of incidence of the light, θ₁ = 35°

The refractive index of air, n₂ = 1.0

Snell's law states that n₁·sin(θ₁) = n₂·sin(θ₂)

Where;

θ₂ = The angle of refraction of the light, which is the angle the light will have when it passes from the glass into the air

Therefore;

θ₂ = arcsin(n₁·sin(θ₁)/n₂)

Plugging in the values of n₁, n₂ and θ₁ gives;

θ₂ = arcsin(1.50 × sin(35°)/1.0) ≈ 59.357551° ≈ 59.4°

The angle the light will have when it passes from the glass into the air, θ₂ ≈ 59.4°.

6 0

3 years ago

How much brighter is Vega than the Sun? (astronomy)

fenix001 [56]

Answer: 60 times brighter

4 0

2 years ago

An astronaut floating at rest in space throws a wrench in one direction and subsequently recoils back with a velocity in the opp

Jobisdone [24]

Answer:

a) ll and Ill only

Explanation:

Let the mass of the wrench = m

and the mass of the astronaut = M

Initially, the velocity of the astronaut and wrench are zero.

The astronaut throws the wrench in one direction and subsequently recoils back with a velocity in the opposite direction.

Let v and V be the velocity of the wrench and the velocity of the astronaut respectively.

In space, there is no external force acting, the momentum must be conserved.

So, m(0)+M(0)=m(v)+M(V)

So, 0=mv+MV

$\Rightarrow mv=-MV$ ...(i)

Here, the momentum of the wrench = mv, and the momentum of the astronaut= MV. The negative sign showing that both the momentum are in opposite direction.

Therefore, the momentum of the wrench is equal and opposite to the momentum of the astronaut.

According to Newton's second law, the rate of change of momentum = applied force.

Let it take $\Delta t$ seconds to change the momentum.

So, for the wrench

$m(v-0)/\Delta t= F_w \\\\\Rightarrow m(v-0)=F_w\Delta t \\\\\Rightarrow mv=F_w\Delta t \cdots(ii)$

Here, $F_w\Delta t$ is the impulse applied to the wrench.

Similarly, for the astronaut

$M(-V-0)/\Delta t= F_a$ [negative sign (-V) for opposite direction]

$\Rightarrow M(-V-0)=F_a\Delta t \\\\\Rightarrow -MV=F_a\Delta t$

Here, $F_a\Delta t$ is the impulse applied to the astronaut.

So, the impulse on the astronaut.

By using equations (i) and (ii)

$F_a\Delta t=F_w\Delta t$

Therefore, the impulse applied to the wrench is equal and opposite to the impulse applied to the astronaut.

Hence, option (a) is correct.

3 0

3 years ago