Question

A sprinter goes off the starting block for 100 m run
and at that instant the second-hand of a watch had
pointed towards North. He touches the finishing line
exactly after 12 seconds. In which direction did the
second hand point when he just crossed the finishing
line?​

Answer 1

Given:

A sprinter goes off the starting block for 100 m run  and at that instant the second-hand of a watch had  pointed towards North.

He touches the finishing line  exactly after 12 seconds.

To find:

In which direction did the  second hand point when he just crossed the finishing  line?​

Solution:

We know that, after every second, the seconds hand make an angle of 6°

So, after 12 sec, seconds hand will make angle of

= 6° ×  12 sec

= 72°

Therefore, it will be 90° − 72° = 18°

In 72° North of East direction the  second hand point when he just crossed the finishing  line.