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3 years ago

- A 9,300 kg. railroad car traveling at a velocity of 15m/s strikes a second boxcar

Physics

1 answer:

VARVARA [1.3K]3 years ago

5 0

Answer:

13950kg

Explanation:

If we make the system both railroad cars, we know that the momentum of the whole system doesn't change because the forces are internal.

Let a be the mass of the second car.

The original momentum is 9300*15 kg*m/s+ a*0 kg*m/s = 139500 kg*m/s

After sticking together, the momentum is (9300+a)kg*6m/s, which should be equal to 139500 kg*m/s

Therefore (9300+a)*6 = 139500

9300+a = 23250

a = 13950 kg

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What is the force on an object that goes from 35 m/s to 85 m/s in 20 seconds and has a mass of 148 kg

Sever21 [200]

F=ma
F = 148×(85-35)÷20
F = 148×(50÷20)
F = 148×2.5
F = 370N

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3 years ago

It is claimed that if a lead bullet goes fast enough, it can melt completely when it comes to a halt suddenly, and all its kinet

TEA [102]

Answer:

$v=346.05\ m.s^{-1}$

Explanation:

Given:

initial temperature of the lead bullet, $T_i=43^{\circ}C$

latent heat of fusion of lead, $L_f=2.32\times 10^4\ J.kg^{-1}$

melting point of lead, $T_m=327.3^{\circ}C$

We have:

specific heat capacity of lead, $c=129\ J.kg^{-1}.K^{-1}$

According to question the whole kinetic energy gets converted into heat which establishes the relation:

$\rm KE=(heat\ of\ rising\ the\ temperature\ from\ 43\ to\ 327.3\ degree\ C)+(heat\ of\ melting)$

$\frac{1}{2} m.v^2=m.c.\Delta T+m.L_f$

$\frac{1}{2} m.v^2=m(c.\Delta T+L_f)$

$\frac{v^2}{2} =129\times(327.3-43)+23200$

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3 years ago

When is a zero not significant?

maria [59]

Answer:

Not between significant digits.

Explanation:

A zero not significant when it's not between significant digits.

8 0

3 years ago

Read 2 more answers

The current through a 10 ohm resistor is 1.2 amperes.What is the potential difference across the resistor?

Natalija [7]

Answer: The potential difference across the resistor is 12 volts.

Explanation:

To calculate the potential difference cross the resistor, we use Ohm's Law. This law states that the potential difference across two wires is directly proportional to the current flowing through that wire.

Mathematically,

$V\propto I\\V=IR$

Where,

V = potential difference = ?V

I = Current flowing = 1.2 A

R = Resistor = $10\Omega$

Putting values in above equation, we get:

$V=1.2\times 10=12V$

Hence, the potential difference across the resistor is 12 volts

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3 years ago

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zysi [14]

Answer:

internet of things.

Explanation:

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