Answer:
Explanation:
The wording on some of these choices is very strange; I'm not sure exactly what they are stating. First of all, A. is definitely a choice because if both the charges were opposite, they would be attracted to one another as opposed to be repelled away from one another, as they are when they are both positive. What happens is that the charges go OUT from the positive charge and INTO the negative; so as far as the field lines around both charges would change direction...no; only the direction of the field lines would change on the positive charge (which is the one on the left). In that space where D is filled in by the field lines going OUT of the positive charge and INTO the negative one, the lines there are naturally closer together, and that is the point where the charge is the greatest. So if that is what is meant by the field lines getting closer together, then yes, they do. As far as choice D. again the field lines on the negative charge don't change, only the ones on the positive charge change.
Answer:
Explanation:
radius of cylinder r₁ = .02 m
radius of safety valve r₂ = .0075 m
force exerted by spring on safety valve = 950 x .0085 = 8.075 N .
Force required on piston of cylinder = F
Applying Pascal's law
8.075 / 3.14 x .0075² = F / 3.14 x .02²
F = 8.075 x .02² / .0075²
= 8.075 x 7.111
= 57.42 N .
Answer:
v = 10 [m/s].
Explanation:
The largest mass is that of 4 [kg], in this way the momentum can be calculated by means of the product of the mass by velocity.
where:
P = momentum [kg*m/s]
m = mass = 4 [kg]
v = velocity = 5 [m/s]
Now the momentum:
![P=4*5\\P=20[kg*m/s]](https://tex.z-dn.net/?f=P%3D4%2A5%5C%5CP%3D20%5Bkg%2Am%2Fs%5D)
This same momentum is equal for the other mass, in this way we can find the velocity.
![P=m*v\\20=2*v\\v=10[m/s]](https://tex.z-dn.net/?f=P%3Dm%2Av%5C%5C20%3D2%2Av%5C%5Cv%3D10%5Bm%2Fs%5D)
Answer:
9.6 rad/s
Explanation:
= length of the metal rod = 50 cm = 0.50 m
= Mass of the long metal rod = 780 g = 0.780 kg
Moment of inertia of the rod about one end is given as
= force applied by the hammer blow = 1000 N
Torque produced due to the hammer blow is given as
= time of blow = 2.5 ms = 0.0025 s
= Angular velocity after the blow
Using Impulse-change in angular momentum, we have
<u>Answer:</u>
2.39 kg
<u>Explanation:</u>
There is conservation of momentum here in this problem so we will use the following problem:
where the mass of the student 
is 48.5 kg,
the mass of the skateboard 
is kg,
the initial speed of the student 
is 4.25 m/s; and
the speed of the student and skateboard 
is 4.05 m/s.
So substituting the given values in the above formula to get:
Therefore, the mass of the skateboard is 2.39 kg.
