Answer:
she must increase the current by factor of 7
Explanation:
The magnetic field produced by a steady current flowing in a very long straight wire encircles the wire.In order to solve the question, we use this formula,
B= μo I/(2πr)
where,
'μo' represents permeability of free space i.e 4π*10-7 N/A2
B=magnetic field
I= current
r=radius
->When r= 1cm=> 0.01m
B1 = μo
/(2π x 0.01)
->when r=7cm =>0.07m
B2 = μo
/(2π x 0.07)
Now equating both of the magnetic fields, we have
B1= B2
μo
/(2π x 0.01)= μo
/(2π x 0.07)
/
= 0.01/0.07
/
= 1/ 7
Therefore, she must increase the current by factor of 7
- The wavelength of the red light in "nanometer" is 7×

- Wavelength is given as : 7×
meter
- 1 nanometer = (
meter)
- Let X= value of the wavelength in nanometer.
1 nanometer =
meter
X nanometer = 7×
meter
- <em>If we Cross multiply</em>
X nanometer = (
)
X= 7×
nanometer
Therefore, the wavelength in "nanometer" is 7×
Learn more at :brainly.com/question/12924624?referrer=searchResults
The goalkeeper at his goal cannot kick a soccer ball into the opponent’s goal without the ball touching the ground
Explanation:
Consider the vertical motion of ball,
We have equation of motion v = u + at
Initial velocity, u = u sin θ
Final velocity, v = 0 m/s
Acceleration = -g
Substituting
v = u + at
0 = u sin θ - g t

This is the time of flight.
Consider the horizontal motion of ball,
Initial velocity, u = u cos θ
Acceleration, a =0 m/s²
Time,
Substituting
s = ut + 0.5 at²

This is the range.
In this problem
u = 30 m/s
g = 9.81 m/s²
θ = 45° - For maximum range
Substituting

Maximum horizontal distance traveled by ball without touching ground is 45.87 m, which is less than 95 m.
So the goalkeeper at his goal cannot kick a soccer ball into the opponent’s goal without the ball touching the ground
a.
The work done by a constant force along a rectilinear motion when the force and the displacement vector are not colinear is given by:

where F is the magnitude of the force, theta is the angle between them and d is the distance.
The problen gives the following data:
The magnitude of the force 750 N.
The angle between the force and the displacement which is 25°
The distance, 26 m.
Plugging this in the formula we have:

Therefore the work done is 17673 J.
b)
The power is given by:

the problem states that the time it takes is 6 s. Then:

Therefore the power is 2945.5 W
Answer:
Distance will be 49.34 m
Explanation:
We have given wavelength 
Diameter of the antenna d = 2.7 m
Range L = 7.8 km = 7800 m
We have to find the smallest distance hat two speedboats can be from each other and still be resolved as two separate objects D
We know that distance is given by 
So distance D will be 49.34 m