How could a slow moving train had the same momentum as a high-speed bullet

Nikolas had an idea that he could use the compressed carbon dioxide in a fire extinguisher to propel him on his skateboard.

Vikentia [17]

The Newton’s law Nikolas would use to come up with this idea is the Third law that states:

When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.

So, in this case, let's name the first Body A which is the skateboard and the second body B which is the compressed carbon dioxide in a fire extinguisher. Then, as shown in the figure below, according to the Third law:

 $FA = -FB$

8 0

3 years ago

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Would you hear an echo if you shouted in your bedroom? Explain your answer.

Sindrei [870]

Answer:

if your bedroom is empty yes but if not most likely no

Explanation:

Why Cannot we hear an echo in a small room?

They can't hear an echo in small room because in it the sound can't be reflected back. For an echo of a sound to be heard,the minimum distance between the source of sound and the walls of the room should be 17.2 m.Obviously,in a small room echoes cannot be heard.

8 0

4 years ago

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What is the Mirror equation? What does it look like?

kipiarov [429]

Answer:

1/f = 1/D' + 1/D

The magnification equation relates the ratio of the image distance and object distance to the ratio of the image height (h^i) and object height (h^o). The magnification equation is stated as follows:

M= H^i/H^o = D^i/D^o

7 0

3 years ago

A trick shot archer shoots an arrow with a velocity of 30.0 m/s at an angle of 20.0 degrees with respect to the horizontal. An a

svlad2 [7]

Answer:

$u'=10.259\ m.s^{-1}$ is the initial velocity of tossing the apple.

the apple should be tossed after $\Delta t=0.0173\ s$

Explanation:

Given:

velocity of arrow in projectile, $v=30\ m.s^{-1}$

angle of projectile from the horizontal, $\theta=20^{\circ}$

distance of the point of tossing up of an apple, $d=30\ m$

Now the horizontal component of velocity:

$v_x=v\ cos\ \theta$

$v_x=30\times cos\ 20^{\circ}$

$v_x=28.191\ m.s^{-1}$

The vertical component of the velocity:

$v_y=v.sin\ \theta$

$v_y=30\times sin\ 20^{\circ}$

$v_y=10.261\ m.s^{-1}$

Time taken by the projectile to travel the distance of 30 m:

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

$t=\frac{30}{28.191}$

$t=1.0642\ s$

Vertical position of the projectile at this time:

$h=v_y.t-\frac{1}{2}g.t^2$

$h=10.261\times 1.0642-\frac{1}{2} \times 9.8\times 1.0642^2$

$h=5.3701\ m$

Now this height should be the maximum height of the tossed apple where its velocity becomes zero.

$v'^2=u'^2-2g.h$

$0^2=u'^2-2\times 9.8\times 5.3701$

$u'=10.259\ m.s^{-1}$ is the initial velocity of tossing the apple.

Time taken to reach this height:

$v'=u'-g.t'$

$0=10.259-9.8\times t'$

$t'=1.0469\ s$

We observe that $t>t'$ hence the time after the launch of the projectile after which the apple should be tossed is:

$\Delta t=t-t'$

$\Delta t=1.0642-1.0469$

$\Delta t=0.0173\ s$

8 0

4 years ago

A resistor and a capacitor are connected in series across an ideal battery having a constant voltage across its terminals. (a) A

mariarad [96]

Answer:

The question is not complete. see the complete question in the explanation section. The correct option is highlighted in bold

Explanation:

(a)A resistor and a capacitor are connected in series across an ideal battery having a constant voltage across its terminals. At the moment contact is made with the battery, the voltage across the resistor is

I. greater than the battery's terminal voltage.

II. equal to the battery's terminal voltage.

III. less than the battery's terminal voltage, but greater than zero.

IV. zero.

Option (i) is not correct as the voltage across the resistor cannot be greater than the terminal voltage since the current is yet to flow through the resistor. Option (ii) is correct as both the resistor voltage and the terminal voltage will just equal at the instance of connection. Option (ii) can only be possible after the current must have passed through the resistor for a while not immediately after contact. Option (iv) is not correct, as this can only be possible is the contact is open.

(b)A resistor and a capacitor are connected in series across an ideal battery having a constant voltage across its terminals. At the moment contact is made with the battery the voltage across the capacitor is

I. greater than the battery's terminal voltage.

II. equal to the battery's terminal voltage.

III. less than the battery's terminal voltage, but greater than zero.

IV. zero.

Option (i) is not correct as the capacitor is yet to charge talk less of the its voltage exceeding that of the battery. Option (ii) can only be correct if the capacitor is fully charged not when it has just been connected. Option (iii) can only occur if the capacitor is discharging. Option (iv) is the correct answer as the capacitor is about to start charging

8 0

4 years ago