Answer:
The correct answer - c. 12.
Explanation:
Given:
Total distance: 6 km
Total time - 45 minutes
covered distance - one half of 6 km = 3 km
time used - 2/3*45 = 30 minutes
Solution:
Remaining distance - 6-3 = 3 km
Remaining time = 45 - 30 = 15 minutes or 1/4 hour
Required speed = remaining distance/ remaining time
=
=
= 12 km/hr
Answer:
A green object will absorb all light except for green light and reflect blue and yellow light.
Answer:
Explanation:
First of all, we analyze the system of blocks before starting to move.
Hence, the incline angle θ for which both blocks begin to slide is 10.20°.
Now, if we do a free body diagram of block A we have that after the block moves, the spring force must be taken into account.
Where:
Therefore, the required stretch or compression in the connecting spring is 0.10 ft.
I hope it helps you!
Answer:
a) True. Diffraction decreases with decreasing wavelength
c) True. As the diameter increases the diffraction decreases, we can observe closer stars
Explanation:
To solve two distant stars we must use Rayleygh's criterion that establishes that two objects are separated if the central maximum of one coincides with the first minimum of the other, applying this to the expression for the diffraction of a slit
a sin θ = m λ
with m = 1
as the telescope has surgical objects, we must solve the problem in polar coordinates, leaving the expression
a sin θ = 1.22 λ
sin θ = 1.22 λ/a
now we can analyze the different statements
a) True. Diffraction decreases with decreasing wavelength
b) False. The focal length influences the magnification, the size of the image, but not the resolution of the same
c) True. As the diameter increases the diffraction decreases, we can observe closer stars
d) False. The focal length influences the magnification not the resolution,
Explanation:
velocity = 15 km/hr = 15×1000m / 60×60s
= 4.17 m/s
time= 20 min= 20 × 60s
= 1200s
displacement =?
we know that,
V = D / t
or, 4.17 = D / 1200
or, D = 4.17 × 1200
or,D = 5004 m