Answer:
Explanation:
The rest energy is the energy associated with the base ball at zero velocity which is expressed as
Note: the speed C is the speed of light which is expressed as 3*10^8
while the kinetic energy is the energy associated with the ball during its motion and is expressed as
the ratio can be expressed as
Explanation:
As you can see in the picture, we want the swimmer to go on a straight line, so the speed of the water must be equal to the speed of the swimmer along the x-axis. We also know the value of v, so we can calculate the of the cosine of the angle (alpha) between Vx and V. Thanks to the fundamental relation of gioniometry (cos^2(x) + sin^2(x) = 1) we can find the sine of alpha and calculate Vy. With Vy we can calculate the time that the swimmer will use for reaching the dock: s = Vy * t => t = s/(Vy).
I'll let you do all the calculations, you just have to plug in values.
