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3 years ago

In which is momentum conserved: an elastic collision or an inelastic collision?

1 answer:

6 0

Energy and momentum are always conserved. Kinetic energy is not conserved in an inelastic collision, but that is because it is converted to another form of energy (heat, etc.). The sum of all types of energy (including kinetic) is the same before and after the collision.

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Velocity and acceleration are both vectors; they have a direction. What is thedirection of the velocity and acceleration vectors

just olya [345]

Answer:

d. Both A & C

Explanation:

- The velocity of the ball is a vector, whose magnitude indicates its rate of change of position, and it has a direction. In this case, the ball is moving upward, therefore the direction of motion is upward, so the direction of the velocity is upward as well.

- The acceleration of the ball is a vector, whose magnitude indicates the rate of change of the velocity. The direction of the acceleration is:

-- positive if the the magnitude of the velocity is increasing

-- negative if the magnitude of the velocity is decreasing

For a ball thrown upward, the acceleration is given by the acceleration of gravity, $g=9.8 m/s^2$ . This acceleration points downward, and it is constant during the entire motion. In particular, it does not change direction, as it is always directed downward. Therefore, the acceleration of the ball is downward.

So, the correct answer is

d.Both A & C

Since A and C are both true:

a.The velocity vector is directed upward.

c.The acceleration is directed downward.

3 0

3 years ago

A research submarine has a 10-cm-diameter window that is 8.4 cm thick. The manufacturer says the window can withstand forces up

Dmitrij [34]

Pnet = Po + dgh

Density of saltwater = 1030 kg/m^3. 

Disregard the thickness. Assuming it's a circular window, then the area is pi(r^2). 

d = 20 cm = 0.2 m 
r = d/2 = 0.1 m 

A = pi(r^2) 
A = 3.14159265(.1^2) 
A = 0.0314159265 m^2 

p = F/A 
p = (1.1 x 10^6) / (0.0314159265) 
p = 35,014,087.5 Pa 

1 atm = 101,325 Pa 

P = Po + dgh 
h = (P - Po) / dg 
h = (35,014,087.5 - 101,325) / (1030 x 9.81) 
h = 3 455.23812 m 
h = 3.5 km

8 0

3 years ago

Read 2 more answers

Consider that 168.0 J of work is done on a system and 305.6 J of heat is extracted from the system. In the sense of the first la

Ilia_Sergeevich [38]

To solve this problem we must resort to the Work Theorem, internal energy and Heat transfer. Summarized in the first law of thermodynamics.

$dQ = dU + dW$

Where,

Q = Heat

U = Internal Energy

By reference system and nomenclature we know that the work done ON the system is taken negative and the heat extracted is also considered negative, therefore

$W = -168J \righarrow$ Work is done ON the system

$Q = -305.6J \rightarrow$ Heat is extracted FROM the system

Therefore the value of the Work done on the system is -158.0J

3 0

3 years ago

1. A step-up transformer increases 15.7V to 110V. What is the current in the secondary as compared to the primary? Assume 100 pe

Serjik [45]

1. $I_2 = 0.14 I_1$

Explanation:

We have:

$V_1 = 15.7 V$ voltage in the primary coil

$V_2 = 110 V$ voltage in the secondary coil

The efficiency of the transformer is 100%: this means that the power in the primary coil and in the secondary coil are equal

$P_1 = P_2\\V_1 I_1 = V_2 I_2$

where I1 and I2 are the currents in the two coils. Re-arranging the equation, we find

$\frac{I_2}{I_1}=\frac{V_1}{V_2}=\frac{15.7 V}{110 V}=0.14$

which means that the current in the secondary coil is 14% of the value of the current in the primary coil.

2. 5.7 V

We can solve the problem by using the transformer equation:

$\frac{N_p}{N_s}=\frac{V_p}{V_s}$

where:

Np = 400 is the number of turns in the primary coil

Ns = 19 is the number of turns in the secondary coil

Vp = 120 V is the voltage in the primary coil

Vs = ? is the voltage in the secondary coil

Re-arranging the formula and substituting the numbers, we find:

$V_s = V_p \frac{N_s}{N_p}=(120 V)\frac{19}{400}=5.7 V$

5 0

3 years ago

Does the earths magnetic field change with time?

ZanzabumX [31]

Answer:

As per the fossil fuel records, magnetic field reversal does not impact living beings. It will take almost a century for the poles to complete the shift. Meanwhile, the earth is left with almost zero magnetic field.

6 0

3 years ago