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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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(When solving for Resistance in a circuit and both voltage and current are known values, the equation I =V*R is not true, and not the way to solve it.) If the resistance is what you're looking for, then the equation to use is R = V / I .

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3 years ago

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A 120 resistor a 60 ohm resistor and a 40 ohm resistor are connected in parallel to a 120 volt power source. what is the current

larisa [96]

Answer:

6 A

Explanation:

First of all, we need to calculate the equivalent resistance of the circuit. The three resistors are connected in parallel, so their equivalent resistance is given by:

$\frac{1}{R_T}=\frac{1}{R_1}+\frac{1}{R_2}+\frac{1}{R_3}=\frac{1}{120 \Omega}+\frac{1}{60 \Omega}+\frac{1}{40 \Omega}=\frac{3+2+1}{120 \Omega}=\frac{6}{120 \Omega}\\R_T = \frac{120}{6} \Omega$

And now we can use Ohm's law to find the current in the circuit:

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3 years ago

There are great similarities between electric and gravitational fields. A room can be electrically shielded so that there are no

ella [17]

Answer:

Can a room be gravitationally shielded? No, it can't.

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the room cannot be gravitationally shielded because there is only one gravitational charge, in this case is mass. Mass can always be positive. the room can be electrically shielded because there are two type of charge, positive and negative charge than can cancel each other out.

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2 years ago

7. Katie and her best friend Liam play tennis every Saturday morning. When Katie serves the ball to Liam, it

KIM [24]

a. 4.52 m/s south

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$v=\frac{d}{t}$

where

d is the displacement

t is the time

Velocity is a vector, so it also has a direction, which corresponds to that of the displacement.

For the ball in this problem,

d = 9.5 m south

t = 2.1 s

Substituting, we find:

$v=\frac{9.5}{2.1}=4.52 m/s$

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$|v| = 4.52 m/s$