Momentum is conserved if and only if sum of all forces which are exserted on system equals zero. In our situation there are only internal forces, so by Newton's third law their vector sum is 0.

So $mv=(m+M)v' \Leftrightarrow v'=\frac{mv}{m+M}$ .

Kinetic energy of system at first: $\frac{mv^2}{2}=784\;\textbf{J}$ . After: $\frac{(m+M)\frac{m^2v^2}{(m+M)^2} }{2}=\frac{m^2v^2}{2(m+M)}\approx 1,96\; \textbf{J}$ . The secret is that other energy is in work of deformation forces (they in turn heat a bullet and a block).

Answer is A)

5 0

3 years ago

The ancient Greek recommendation of rest in the treatment of abnormal behavior soon gave rise to ______. A. Trephining B. The as

Lilit [14]

C. Is the correct answer

7 0

3 years ago

For the circuit in the previous part, what happens to the maximum current if the frequency is doubled and the inductance is halv

tamaranim1 [39]

Answer:

Following are the responses to these question:

Explanation:

Since the $max^{m}$ is the current of ckt which depend on the reactance which inductor that also enables the ckt and inductor resistance $(X_L)$ for capacities

$\to X_{C}=\frac{1}{W L}$

for

$\to X_{L}=wL$

When $w \longrightarrow 2w$

$L\longrightarrow \frac{L}{2}$

then

$\to X_{L}=2 w \times \frac{L}{2}=wL$

therefore, $X_{L}$ remains at the same so, the maximum current remains the in same ckt.

4 0

2 years ago

An LR circuit contains an ideal 60-V battery, a 42-H inductor having no resistance, a 24-ΩΩ resistor, and a switch S, all in ser

s2008m [1.1K]

Answer:

1.6 s

Explanation:

To find the time in which the potential difference of the inductor reaches 24V you use the following formula:

$V_L=V_oe^{-\frac{Rt}{L}}$

V_o: initial voltage = 60V

R: resistance = 24-Ω

L: inductance = 42H

V_L: final voltage = 24 V

You first use properties of the logarithms to get time t, next, replace the values of the parameter:

$\frac{V_L}{V_o}=e^{-\frac{Rt}{L}}\\\\ln(\frac{V_L}{V_o})=-\frac{Rt}{L}\\\\t=-\frac{L}{R}ln(\frac{V_L}{V_o})\\\\t=-\frac{42H}{24\Omega}ln(\frac{24V}{60V})=1.6s$

hence, after 1.6s the inductor will have a potential difference of 24V

3 0

3 years ago

In a blood pressure reading of 110/70, 110 represents ________ pressure and 70 represents ________ pressure.

In a blood pressure reading of 110/70, 110 represents pressure and 70 represents pressure.