The time per lap was calculated by measuring the time for seven laps and dividing the total time by seven.
total time
It is given that the precision is of 0.1 s. it means it is correct upto 1 place beyond decimal.
So, the actual value could vary from 457.800 s to 457.899 s i.e. the time per lap could be 65.400 s to 65.414 s
It means measured time 65.414 s has maximum error of 0.021%. Hence, the measured value is quite precise.
Let be the direction the swimmer must swim relative to east. Then her velocity relative to the water is
The current has velocity vector (relative to the Earth)
The swimmer's resultant velocity (her velocity relative to the Earth) is then
We want the resultant vector to be pointing straight north, which means its horizontal component must be 0:
which is approximately 41º west of north.
Answer:
Explanation:
To solve this problem we use the Momentum's conservation Law, before and after the girl catch the ball:
(1)
At the beginning the girl is stationary:
(2)
If the girl catch the ball, both have the same speed:
(3)
We replace (2) and (3) in (1):
We can now solve the equation for v_{f}: