Answer:

Explanation:
given,
refractive index of lens, n = 1.70
Radius of curvature of front surface. R₁ = 20 cm
Radius of curvature of the back surface, R₂ = 30 cm
focal length= ?

R₁ = +20 cm
R₂ = -30 cm
n = 1.70




the focal length of the lens is equal to 17.15 cm
Answer:
a.
Explanation:
cuz whenever the ball was traveling up the staircase it was building up energy to use (potential energy) unlike b.
Answer:
Saturn's differential rotation will cause the length of a day measures to be longer by 0.4 hours
Explanation:
Differential rotation occurs due to the difference in angular velocities of an object as we move along the latitude of the or as we move into different depth of the object, indicating the observed object is in a fluid form
Saturn made almost completely of gas and has differential motion given as follows
Rotation at the equator = 10 hours 14 minutes
Rotation at high altitude = 10 hours 38 minutes
Therefore;
The differential rotation = 10 hours 38 minutes - 10 hours 14 minutes
The differential rotation = 24 minutes = 24 minutes × 1 hour/(60 minutes) = 0.4 hours
The differential rotation = 0.4 hours
Therefore, the measured day at the higher altitude will be 0.4 longer than at the equator.
Answer:
P = 17.28*10⁶ N
Explanation:
Given
L = 250 mm = 0.25 m
a = 0.54 m
b = 0.40 m
E = 95 GPa = 95*10⁹ Pa
σmax = 80 MPa = 80*10⁶ Pa
ΔL = 0.12%*L = 0.0012*0.25 m = 3*10⁻⁴ m
We get A as follows:
A = a*b = (0.54 m)*(0.40 m) = 0.216 m²
then, we apply the formula
ΔL = P*L/(A*E) ⇒ P = ΔL*A*E/L
⇒ P = (3*10⁻⁴ m)*(0.216 m²)*(95*10⁹ Pa)/(0.25 m)
⇒ P = 24624000 N = 24.624*10⁶ N
Now we can use the equation
σ = P/A
⇒ σ = (24624000 N)/(0.216 m²) = 114000000 Pa = 114 MPa > 80 MPa
So σ > σmax we use σmax
⇒ P = σmax*A = (80*10⁶ Pa)*(0.216 m²) = 17280000 N = 17.28*10⁶ N