Answer:
friction can be used to slow things down but it can also be harmful because it can cause fire to start
Answer:
Explanation:
Change in length of spring = 2.13 m
Component of weight acting on spring = mg sinθ
so
mg sinθ = k x where k is spring constant and x is total stretch due to force on the spring.
Here x = 2.13
mg sin17 = k x 2.13
31 x 9.8 sin17 = k x 2.13
k = 41.7 N/m
b ) In case surface had friction , spring would have stretched by less distance .
It is so because , the work done by gravity in stretching down is stored as potential energy in spring . In case of dissipative force like friction , it also takes up some energy in the form of heat etc so spring stretches less.
Answer:
134.77 mm
Explanation:
Wave length of light λ = 599 x 10⁻⁹ m
Slit separation d = 20 x 10⁻⁶ m
Screen distance D = 3 m
Distance of second dark fringe from centre
= 1.5 x λ D / d
Putting the values given above
distance = 
= 134.77 x 10⁻³ m
= 134.77 mm.
The best conclusion that can be drawn is that D) A current does not flow in the wire
Answer:
x = 727.5 km
Explanation:
With the conditions given using trigonometry, we can find the tangent
tan θ = CO / CA
With CO the opposite leg and CE is the adjacent leg which is the distance from the Tierral to Sun
D =150 10⁶ km (1000m / 1 km)
D = 150 10⁹ m.
We must take the given angle to radians.
1º = 3600 arc s
π rad = 180º
θ = 1 arc s (1º / 3600 s arc) (pi rad / 180º) =
θ = 4.85 10⁻⁶ rad
That angle is extremely small, so we can approximate the tangent to the angle
θ = x / D
x = θ D
x = 4.85 10-6 150 109
x = 727.5 103 m
x = 727.5 km
