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:

Explanation:
We can calculate the acceleration experimented by the passenger using the formula
, taking the initial direction of movement as the positive direction and considering it comes to a rest:

Then we use Newton's 2nd Law to calculate the force the passenger of mass m experimented to have this acceleration:

Which for our values is:

Answer: 7200 m
Explanation: The solution is, first convert 15 minutes to seconds.
15 mins x 60 s / 1 min = 900 s
Use the formula for speed which is v= d/t then derive for d.
d = vt
= 8 m/s ( 900s)
= 7200 m