Answer:
3433.5 N
Explanation:
g = Acceleration due to gravity = 9.81 m/s²
m = Mass of person = 70 kg
According to the question
a = Acceleration

Balancing the forces we have

The required force is 3433.5 N
Answer:
A. 39.2 m/s
B. 78.4 m
Explanation:
Data obtained from the question include:
Time (t) = 4 s
Acceleration due to gravity (g) = 9.8 m/s²
A. Determination of the brick's velocity.
Time (t) = 4 s
Acceleration due to gravity (g) = 9.8 m/s²
Velocity (v) =?
v = gt
v = 4 × 9.8
v = 39.2 m/s
Thus, the brick's velocity after 4 s is 39.2 m/s
B. Determination of how far the brick fall in 4 s.
Time (t) = 4 s
Acceleration due to gravity (g) = 9.8 m/s²
Height (h) =?
h = ½gt²
h = ½ × 9.8 × 4²
h = 4.9 × 16
h = 78.4 m
Thus, the brick fall 78.4 m during the time.
In order to answer this exercise you need to use the formulas
S = Vo*t + (1/2)*a*t^2
Vf = Vo + at
The data will be given as
Vf = final velocity = ?
Vo = initial velocity = 1.4 m/s
a = acceleration = 0.20 m/s^2
s = displacement = 100m
And now you do the following:
100 = 1.4t + (1/2)*0.2*t^2
t = 25.388s
and
Vf = 1.4 + 0.2(25.388)
Vf = 6.5 m/s
So the answer you are looking for is 6.5 m/s
The index of refraction of a material is the ratio between the speed of light in vacuum, c, and the speed of light in that material, v:

where the speed of light in vacuum is

. The speed of light in benzene is

, so we can use the previous relationship to find the refractive index of benzene: