91影视

The given data can be listed below.

• The speed of the sidewalk is, v_s= 1m/s
• The length of the sidewalk is, d = 35m
• The relative speed of a woman with respect to the sidewalk is, v_ws = 1.5m/s

The relative speed is equal to the difference between the speeds of two objects traveling in the same direction at different speeds.

Their relative speed is equal to the total of their speeds if they are going in the opposite direction.

The woman's net velocity would equal the sum of the two velocities if she were going in the same direction as the sidewalk's motion given by,

v_nw = v_s+v_ws

Here, v_s is the velocity of the sidewalk and v_ws is the velocity of the woman.

Substitute all the values in the above,

$\begin{array}{rcl}{v}_{nw}& =& 1.5m/s+1m/s\\ & =& 2.5m/s\end{array}$

The time taken by woman to reach other side of sidewalk is given by,

$t=\frac{d}{v}$

Here, d is the length of the sidewalk and v is the velocity of woman.

Substitute all the values in the above,

$\begin{array}{rcl}t& =& \frac{35m}{2.5m/s}\\ & =& 14s\end{array}$

Thus, the time taken by woman to reach the opposite end of sidewalk moving in same direction is 14 s.

The net velocity of a woman when moving opposite direction to the sidewalk is given by,

v_nw = v_ws- v_s

Here, v_s is the velocity of the sidewalk and v_ws is the velocity of the woman.

Substitute all the values in the above,

$\begin{array}{rcl}{v}_{nw}& =& 1.5m/s-1m/s\\ & =& 0.5m/s\end{array}$

The time taken by a woman to reach other side of the sidewalk is given by,

$t=\frac{d}{v_{nw}}$

Substitute all the values in the above,

$\begin{array}{rcl}t& =& \frac{35m}{0.5m/s}\\ & =& 70s\end{array}$

Hence, the time taken by a woman to reach the opposite side of the sidewalk moving in the opposite direction is 70 s.