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3 years ago

Object A travels at a constant velocity of 2.0 m/s right, and object B travels in the same direction at a

Physics

1 answer:

pashok25 [27]3 years ago

8 0

==> Object A travels for 60 seconds before Object B starts out.

==> Object A moves at 2 m/s.

==> So Object A has a lead of 120 m when Object B starts out.

==> Object B moves at 3 m/s . . . 1 m/s faster than Object A.

==> So Object B catches up on Object A by 1 m every second.

==> Object B closes up Object A's lead of 120 m in <em>120 seconds</em>.

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n isolated charged soap bubble of radius R0=7.45 cmR0=7.45 cm is at a potential of V0=307.0 volts.V0=307.0 volts. If the bubble

Gnesinka [82]

Complete Question

An isolated charged soap bubble of radius R0 = 7.45 cm is at a potential of V0=307.0 volts. V0=307.0 volts. If the bubble shrinks to a radius that is 19.0%19.0% of the initial radius, by how much does its electrostatic potential energy ????U change? Assume that the charge on the bubble is spread evenly over the surface, and that the total charge on the bubble r

Answer:

The difference is $U_f -U_i = 16 *10^{-7} J$

Explanation:

From the question we are told that

The radius of the soap bubble is $R_o = 7.45 \ cm = \frac{7.45}{100} = 0.0745 \ m$

The potential of the soap bubble is $V_1 =307.0 V$

The new radius of the soap bubble is $R_1 = 0.19 * 7.45=1.4155\ cm = 0.014155 \ m$

The initial electric potential is mathematically represented as

$U_i = \frac{V_1^2 R_o }{2k }$

The final electric potential is mathematically represented as

$U_f = \frac{V_2^2 R_1 }{2k }$

The initial potential is mathematically represented as

$V_1 = \frac{kQ}{R_o}$

The final potential is mathematically represented as

$V_2 = \frac{kQ}{R_1}$

Now

$\frac{V_2}{V_1} = \frac{R_o}{R_1}$

substituting values

$\frac{V_2}{V_1} = \frac{7.45}{1.4155} = \frac{1}{0.19}$

=> $V_2 = \frac{V_1}{0.19}$

$U_f = \frac{V_1^2 R_2 }{2k * 0.19^2}$

Therefore

$U_f -U_i = \frac{V_1^2 R_2 }{2k * 0.19^2} - \frac{V_1^2 R_o }{2k }$

$U_f -U_i = \frac{V_1^2}{2k} [\frac{ R_1 }{ * 0.19^2} - R_o]$

where k is the coulomb's constant with value $9*10^{9} \ kg\cdot m^3\cdot s^{-4}\cdot A^2.$

substituting values

$U_f -U_i = \frac{307^2}{9 * 10^{9}} [\frac{ 0.014155 }{ 0.19^2} - 0.0745]$

$U_f -U_i = 16 *10^{-7} J$

8 0

3 years ago

A constant net force of 345 N is applied to slide a heavy stationary

liubo4ka [24]

Answer:

P = 517.5 [kg*m/s]

Explanation:

We must remember that momentum is defined as the product of force by the time of force duration.

$P=F*t$

where:

P = momentum [kg*m/s]

F = force [N]

t = time [s]

$P=345*1.5\\P=517.5[kg*m/s]$

4 0

3 years ago

14. A block rests on a frictionless table on Earth. After a 20-N horizontal force is applied to the block, it accelerates at 3.9

joja [24]

<span>14. Let's find mass. We know that F = m*a, so m = F/a.m = 20/3,9 m/s^2 = 5,12 kg;We already know the mass, so acceleration will be a = F/m;a = 10/5,12 = 2,0 m/s^2 (approximately);Answer: E.
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And these are refer to x: $985N cos(31)= 844 788N sin(32)= -417 411N cos(53)= -247$
And finally let's calculate tan: $tan^-1 (507/844)= 30,98; tan^-1 (668/-417)= -58,02; tan^-1 (-328/-247)= 53,01$
According to these calculations we've got: Sum Fx = 179,4 and Sum Fy = 847. Then let's count magnitude: $Fsum = rad 179^2 + 847^2 = 865$
Then we've got [tex]cos^-1 (179/865) = 77.7 (approximately).
So the most approximate answer is C. 866 N at 78.1° counterclockwise to the x-axis.
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19. According to the Work-Energy Theorem we have:1/2*1200*2^2 = 2400 (J);Then let's count the average force according to the formula: Work = F*D where D is displacement.F = 2400/ 0.15 = 16000 (N)
So the answer is B. 1.6 × 10^4 N
20. If my memory serves me well, magnetism is the force that can act through empty space. It's one aspect of the combined electromagnetic force. So the answer is A.
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22. I am definitely sure that the answer is C. on Earth at sea level. Because weight has the formula W=mg. And on the earth surface the magnitude of g is higher that everywhere so the greatest weight is on Earth at sea level.
23. We have everything to calculate the acceleration. According to Newton's second law, the formula is a = F/m;a = 20/40 = 0,5 m/s^2; So the answer is A.
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3 years ago

Read 2 more answers

What is kinetic friction?

Lunna [17]

Answer:

Kinetic friction is an inhibitory force that is present when a body or object begins to move. It should be noted that this force is in the opposite direction to the movement of the body that slides with respect to a surface and parallel to that surface.

In addition, this friction varies according to the surface characteristics and the material properties of the bodies that slide in this surface. Being quantified by the coefficient of kinetic friction $\mu_{K}$ , which is dimensionless.

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4 years ago

Directions: The table shows the mass of several objects. Use the table to answer any questions that follow.

barxatty [35]

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