Answer:
Here is the complete question:
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a) Current for long straight wire 
b) Current at the center of the circular coil 
c) Current near the center of a solenoid 
Explanation:
⇒ Magnetic Field due to long straight wire is given by (B),where

Plugging the values,
Conversion
,and 

⇒Magnetic Field at the center due to circular coil (at center) is given by,
So 
⇒Magnetic field due to the long solenoid,
Then
So the value of current are
,
and
respectively.
Answer:
Explanation:
If the work done on the cart is NET work
Then the work will result in an increase in kinetic energy
KE₀ + W = KE₁
½mv₀² + W = ½mv₁²
½(0.80)(0.61²) + 0.91 = ½(0.80)v₁²
v₁ = 1.626991...
v₁ = 1.6 m/s
Given:
1st run: 20 meters North
2nd run: 15 meters East
time: 15 seconds
Average speed = total distance covered / total time taken
Ave. Speed = (20m + 15m) / 15s
Ave. Speed = 35m / 15s
Ave. Speed = 2 1/3 meters per second
We assume that horn releases sound of constant frequency. In order for observer to observe different frequency either horn or observer or both must move.
This happens due to Doppler effect. It states that when position of source of sound and observer relative to each other changes, the observed frequency also changes. If the source emits sound of constant frequency than observed frequency will be either higher or lower than original.
When distance between source and observer increases the observed frequency will be lower. This is because same number of sound waves must cover greater distance so they have greater wavelength.
When distance between source and observer decreases the observed frequency will be higher. This is because same number of sound waves must cover smaller distance so they have smaller wavelength.
Wavelength and frequency are inversely proportional meaning when one increases the other drecreases.
From this explanation we can find answer for our question. <span>If we wanted the pitch of a horn to drop relative to an observer we need to move horn away from an observer.</span>
The maximum force that the athlete exerts on the bag is equal to 1,500 N and in the opposite direction as the force that the bag exerts on the athlete.
<h3>
Newton's third law of motion</h3>
Newton's third law of motion states that action and reaction are equal and opposite.
Fa = -Fb
The force exerted by the athlete on the bag is equal to the force the bag exerted on the athlete but in opposite direction.
Thus, the maximum force that the athlete exerts on the bag is equal to 1,500 newtons and in the opposite direction as the force that the bag exerts on the athlete.
Learn more about force here: brainly.com/question/12970081
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