Help not to sure with this one need help plz asap
2 answers:
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Answer:
1) is<u> positive.</u>
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2)
Explanation:
<h2><u>Part 1:</u></h2><u></u>
The charged rod is held above the balloon and the weight of the balloon acts in downwards direction. To balance the weight of the balloon, the force on the balloon due to the rod must be directed along the upwards direction, which is only possible when the rod exerts an attractive force on the balloon and the electrostatic force on the balloon due to the rod is attractive when the polarities of the charge on the two are different.
Thus, In order for this to occur, the polarity of charge on the rod must be positive, i.e., is <u>positive.</u>
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<h2><u>Part 2:</u></h2><u></u>
<u>Given:</u>
- Mass of the balloon, m = 0.00275 kg.
- Charge on the balloon,
- Distance between the rod and the balloon, d = 0.0640 m.
- Acceleration due to gravity,
In order to balloon to be float in air, the weight of the balloom must be balanced with the electrostatic force on the balloon due to rod.
Weight of the balloon,
The magnitude of the electrostatic force on the balloon due to the rod is given by
is the Coulomb's constant.
For the elecric force and the weight to be balanced,
a) Same
b) Same
c) Same
d) Throw the ball takes longer
e) F is larger when the ball is catched
Explanation:
a)
The change in speed of an object is given by:
where
u is the initial velocity of the object
v is the final velocity of the object
The change in speed is basically the magnitude of the change in velocity (because velocity is a vector, while speed is a scalar, so it has no direction).
In this problem:
- In situation 1 (pitcher throwing the ball), the initial velocity is
u = 0 (because the ball starts from rest)
while the final velocity is v, so the change in speed is
- In situation 2 (catcher receiving the ball), the initial velocity is now
u = v
while the final velocity is now zero (ball coming to rest), so the change in speed is
Which means that the two situations have same change in speed.
b)
The change in momentum of an object is given by
where
m is the mass of the object
is the change in velocity
If we want to compare only the magnitude of the change in momentum of the object, then it is given by
- In situation 1 (pitcher throwing the ball), the change in momentum is
- In situation 2 (catcher receiving the ball), the change in momentum is
So, the magnitude of the change in momentum is the same (but the direction is opposite)
c)
The impulse exerted on an object is equal to the change in momentum of the object:
where
I is the impulse
is the change in momentum
As we saw in part b), the change in momentum of the ball in the two situations is the same, therefore the impulse exerted on the ball will also be the same, in magnitude.
However, the direction will be opposite, as the change in momentum has opposite direction in the two situations.
d)
To compare the time of impact in the two situations, we have to look closer into them.
- When the ball is thrown, the hand "moves together" with the ball, from back to ahead in order to give it the necessary push. We can verify therefore that the time is longer in this case.
- When the ball is cacthed, the hand remains more or less "at rest", it doesn't move much, so the collision lasts much less than the previous situation.
Therefore, we can say that the time of impact is longer when the ball is thrown, compared to when it is catched.
e)
The impulse exerted on an object can also be rewritten as the product between the force applied on the object and the time of impact:
where
I is the impulse
F is the force applied
is the time of impact
This can be rewritten as
In this problem, in the two situations,
- I (the impulse) is the same in both situations
- when the ball is thrown is larger than when it is catched
Therefore, since F is inversely proportional to , this means that the force is larger when the ball is catched.
The formula for the period of wave is: wave period is equals to 1 over the frequency.
To get the value of period of wave you need to divide 1 by 200 Hz. However, beforehand, you have to convert 200 Hz to cycles per second. So that would be, 200 cyles per second or 200/s.
By then, you can start the computation by dividing 1 by 200/s. Since 200/s is in fractional form, you have to find its reciprocal form and multiply it to one which would give you 1 (one) second over 200. This would then lead us to the value 0.005 seconds as the wave period.
wave period= 1/200 Hz
Convert Hz to cycles per second first
200 Hz x 1/s= 200/second
Make 200/second as your divisor, so:
wave period= 1/ 200/s
get the reciprocal form of 200/s which is s/200
then you can start the actual computation:
wave period= 1 x s divided by 200
this would give us an answer of 0.005 s.
To get the value of period of wave you need to divide 1 by 200 Hz. However, beforehand, you have to convert 200 Hz to cycles per second. So that would be, 200 cyles per second or 200/s.
By then, you can start the computation by dividing 1 by 200/s. Since 200/s is in fractional form, you have to find its reciprocal form and multiply it to one which would give you 1 (one) second over 200. This would then lead us to the value 0.005 seconds as the wave period.
wave period= 1/200 Hz
Convert Hz to cycles per second first
200 Hz x 1/s= 200/second
Make 200/second as your divisor, so:
wave period= 1/ 200/s
get the reciprocal form of 200/s which is s/200
then you can start the actual computation:
wave period= 1 x s divided by 200
this would give us an answer of 0.005 s.
Answer:
160N
Explanation:
Moments must be conserved - so.