Answer:
Explanation:
Given
mass of couch
acceleration of couch
inclination
Let coefficient of kinetic Friction
as couch begins to slides Forces act on couch
, where is friction force
therefore net acceleration is
Answer:Food contains chemical potential energy. As our bodies digest it, the stored energy is converted into energy for us to move and grow.
Explanation:
Answer:
Explanation:
In case of oil slick a thin layer of oil is formed on water . This thin layer creates a rainbow of colour . The phenomenon is due to interference of light waves , one reflected from the upper surface of oil and the other reflected from the lower surface of the oil.
For formation of bright colour
2 μ t = ( 2n + 1 ) λ / 2
μ is refractive index of oil , t is thickness of oil layer λ is wave length of light falling on the layer .
given μ = 1.2 , λ = 750 x 10⁻⁹ ,
2 x 1.2 t = ( 2n + 1 ) 750 x 10⁻⁹ / 2
For minimum thickness n = 0
2.4 t = 375 x 10⁻⁹
t = 156.25 n m
B ) If the refractive index of layer of medium below oil is less than that of oil , the condition of formation of colour changes
The new condition is
2 μ t = n λ
2 x 1.5 t = 750 nm , n = 1 for minimum wavelength .
t = 250 nm
C ) Light mostly transmitted means dark spot is formed at that point .
For that to be observed from water side , the condition is
2 μ t = ( 2n + 1 ) λ / 2
λ = 4μ t / ( 2n + 1 )
For maximum wavelength n = 0
λ = 4μ t
= 4 x 1.5 x 200 nm
= 1200 nm .
Answer:
the ratio of the smallest division of main scale to the number of divisions of the vernier scale.
Explanation:
difference between the value of one main scale division and one vernier scale division
Answer:
7.875 ft/s
Explanation:
L = 15 ft
dx/dt = 3 ft/s
x = 9 ft
Let the top of ladder is coming down with the rate of dy/dt.
use Pythagorean theorem
L^2 = x^2 + y^2 .... (1)
Differentiate both sides with respect to t
0 = 2 x dx/dt + 2y dy/dt
x dx/dt = - y dy/dt
When, x = 9 ft then y = ? . Put this in equation (1)
15^2 = 9^2 + y^2
225 - 81 = y^2
y = 12 ft
So
dy/dt = - x (dx/dt) / y = - 9 (3) / 12 = - 9/4 ft/s
Let A be the area of the triangle
A = 1/2 (base)(height)
A = 1/2 (x y)
Differentiate both sides with respect to t
dA/dt = 0.5 (y dx/dt + x dy/dt)
dA/dt = 0.5 [ 12 (3) - 9 (9/4)]
dA/dt = 0.5(36 - 81 /4) = 31.5 / 4 = 7.875 ft/s