If you can swim in still water at 0.5m/s, the shortest time it would take you to swim from bank to bank across a 20m wide river,
if the water flows downstream at a rate of 1.5m/s, is most nearly:
2 answers:
Answer:42.55 seconds
Explanation:
Check attached file for the diagram.
Vr= velocity of the river, if the water flows downstream, which is equal to 1.5m/s(from the question), Vb= my velocity at angle alpha which is perpendicular to the x-axis, and c= distance to swim from river bank to the other river bank.
Therefore, the shortest time to be taken to swim or cross the river,t=river with width of C÷ vertical component Vj.
Note that (vector) Vj= (vector)Vr+(vector)Vb.
Also, alpha must be maximum and for that to happen it must have a value of one(1).
Hence, time taken to cross the river,t= C/Vb× sin (alpha).
t= 20m÷ 0.5 ×sin 90.
t= 20÷ 0.47.
t= 42.55 seconds.
You might be interested in
Answer:
The temperature is
Explanation:
From the question ewe are told that
The rate of heat transferred is
The surface area is
The emissivity of its surface is
Generally, the rate of heat transfer is mathematically represented as
=>
where is the Boltzmann constant with value
substituting value