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3 years ago

2. Which of the following is a true statement.

Physics

2 answers:

lorasvet [3.4K]3 years ago

5 0

Answer:

Sound travels slower than light

Explanation:

Sound travels at around 1/3 km per second, while light travels around 300,000 km per second.

Also, this is the reason you see the lightning before you hear the thunder.

I hope this helped.

storchak [24]3 years ago

5 0

Answer:

Sound travels slower than light

Explanation:

Bc light is faster than sound

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Running at 2 m/s, Bruce the 45 kg quarterback, collides with Biff, the 90 kg tackle, who is traveling at 7 m/s in the other dire

melomori [17]

Given data

*The mass of Bruce is m_1 = 45 kg

*The initial velocity of the Bruce is u_1 = 2 m/s

*The mass of the biff is m_2 = 90 kg

*The initial velocity of the Biff is u_2 = -7 m/s

*The final velocity of the first glider is v_2 = -1 m/s

According to the law of conservation of linear momentum, the total linear momentum of a system remains constant

Applying the law of conservation of momentum as

$\begin{gathered} p_i=p_f \\ m_1u_1+m_2u_2=m_1v_1+m_2v_2 \\ v_1=\frac{m_1u_1+m_2u_2-m_2v_2_{}_{}_{}_{}}{m_1} \end{gathered}$

Substitute the known values in the above expression as

$\begin{gathered} v_1=\frac{(45)(2)+(90)(-7)-(90)(-1)}{45} \\ =-10\text{ m/s} \end{gathered}$

Hence, the speed of the bruce knock backwards is v_1 = -10 m/s

3 0

2 years ago

A 91.5 kg football player running east at 2.73 m/s tackles a 63.5 kg player running east at 3.09 m/s. what is their velocity aft

pentagon [3]

Answer:

2.877 m/s

Explanation:

According to the laws of conservation of linear momentum,

the momentum of the moving objects before impact is equal to the momentum of the objects after impact (Assuming no external forces were applied)

Let both players are tackled and moving in V velocity

M and m - masses of the players
U and u - velocities of them respectively (both velocities are towards east direction )

momentum before impact = momentum after impact

→MU + →mu = →(M+ m )v

91.5 * 2.73 + 63.5 * 3.09 = (91.5 + 63.5) * V

→V = 2.877 m/s (To East)

3 0

3 years ago

Read 2 more answers

Which products are formed when ethane (C2H6) undergoes combustion?

ANEK [815]

Answer:

Explanation:

It is C.

4 0

3 years ago

Read 2 more answers

A beam of light in air is incident at an angle of 30º to the surface of a rectangular block of clear plastic (n = 1.46). The lig

Aneli [31]

Answer:

θ = 30°

Explanation:

Firts, the angle when the beam of light passes through the block cam be calculated using Snell Law:

$n_{1}sin(\theta_{1}) = n_{2}sin(\theeta_{2})$

<u>Where</u>:

n₁: is the index of refraction of the incident medium (air) = 1

θ₁: is the incident angle = 30°

n₂: is the medium 2 (plastic) = 1.46

θ₂: is the transmission angle

Hence, θ₂ is:

$sin(\theta_{2}) = \frac{n_{1}*sin(\theta_{1})}{n_{2}} = \frac{1*sin(30)}{1.46} = 0.34 \rightarrow \theta_{2} = 20.03 ^{\circ}$

Now, when the beam of light re-emerges from the opposite side, we have:

n₁: is the index of refraction of the incident medium (plastic) = 1.46

θ₁: is the incident angle = 20.03°

n₂: is the medium 2 (air) = 1

θ₂: is the transmission angle

Hence, the angle to the normal to that surface (θ₂) is:

$sin(\theta_{2}) = \frac{n_{1}*sin(\theta_{1})}{n_{2}} = \frac{1.46*sin(20.03)}{1} = 0.50 \rightarrow \theta_{2} = 30 ^{\circ}$

Therefore, we have that the beam of light will come out at the same angle of when it went in, since, it goes from air and enters to a plastic medium and then enters again in this medium to go out to air again. This was proved using the Snell Law.

I hope it helps you!

5 0

3 years ago

The force required to move a chair 4 meters is 3 newton’s. what amount of work is done

zlopas [31]

Answer: 12 J

Explanation:

Work = force*displacement

Work= 3N*4m= 12 Joule

7 0

4 years ago