The average 8- to 18-year-old spends __________ per day on average in front of a screen doing very little to no physical activit
1 answer:
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Answer:
a) 0 m/s
b) - 24 m/s
c) - 68 m
Explanation:
Given:
Initial distance = - 4 m
Initial velocity, u = 4 m/s
1) acceleration, a = - 2 m/s² for time, t = 2 seconds
thus,
velocity after 2 seconds will be
from Newton's equation of motion
v = u + at
v = 4 + (-2) × 2
v = 0 m/s
2) Velocity after 2 second is the initial velocity for this case
given acceleration = - 6 m/s² for 4 seconds
thus,
final velocity, v = 0 + ( - 6 ) × 4 = - 24 m/s
here the negative sign depicts the velocity in opposite direction to the initial direction of motion
thus, velocity after 6 seconds = - 24 m/s
3) Now,
Total displacement in 6 seconds
= Displacement in 2 seconds + Displacement in 4 seconds
From Newton's equation of motion
where,
s is the distance
u is the initial speed
a is the acceleration
t is the time
thus,
= +
= - 16 - 48
= - 64 m
Hence, the final displacement = - 64 - 4 = - 68 m
Answer:
b.
Explanation:
In case of Single Slit, diffraction will occur.
Then In Single slit Diffraction, width of central fringe is
where D= distance b/w screen and slit
a= slit width
\lambda = wavelength
Thus if Screen width increases keeping other factors same then width of central fringe becomes narrower as
On increasing the slit width the central bright fringe width The width of the central bright fringe becomes narrower.