Answer:
The magnetic field in the center of the solenoid is
.
Explanation:
Given that,
Length of solenoid = 0.425 m
Number of turns N = 950
Current I = 2.75 A
The magnetic field in the center of the solenoid is the product of the current , number of turns per unit length and permeability.
In mathematical form,

Where, 
N = number of turns
L = length
I = current
Now, The magnetic field

Put the value into the formula



Hence, The magnetic field in the center of the solenoid is
.
Hey there, the answer is .............................. About 0.7 m/sec^2
<span>
Acceleration is the change in speed / time </span>
<span>Change in speed is 60 m/sec </span>
<span>Time is 1 minute 25 second. Convert that to seconds. </span>
<span>Divide the change in speed by the time in seconds.
About 0.7 m/sec^2
</span><span>So the acceleration is - 60 / 85 = - 0.71 m/s^2
HOPE I HELPED!!!!!!!!!!</span>
The distance covered by car is equal to (assuming it is moving by uniform motion) the product between the car's speed and the time of the car ride, 4 h:

where

is the car's speed

is the duration of the car ride
Similarly, the distance covered by train is equal to the product between the train's speed and the duration of the train ride, 7 h:

The total distance covered is S=255 km, which is the sum of the distances covered by car and train:

which becomes

(1)
we also know that the train speed is 5 km/h greater than the car's speed:

(2)
If we put (2) into (1), we find

and if we solve it, we find


So, the car speed is 20 km/h and the train speed is 25 km/h.
At stp (standard temperature and pressure), the temperature is T=0 C=273 K and the pressure is p=1.00 atm. So we can use the ideal gas law to find the number of moles of helium:

where p is the pressure (1.00 atm), V the volume (20.0 L), n the number of moles, T the temperature (273 K) and

the gas constant. Using the numbers and re-arranging the formula, we can calculate n:
Opportunity cost refers to what you have to give up to buy what you want in terms of other goods or services. When economists use the word “cost,” we usually mean opportunity cost.