The speed of a stream is 3 mph. a boat travels 11 miles upstream in the same time it takes to travel 17 miles downstream. what is the speed of the boat in still water

14mph

Explanation:

let speed in still water be represented as y

The speed of the stream is given as 3mph

distance traveled by boat upstream = 11 Miles

distance traveled by boat downstream = 17 miles

∴ speed when the boat travels upstream = y-3

speed when the boat travels downstream = y+3

speed =

time =

time taken to go upstream =

time taken to go downstream =

assuming that time taken to travel upstream = time taken to travel downstream

=

by cross multiplication,

11(y+3)=17(y-3)

11y + 33 = 17y - 51

17y - 11y = 33 + 51

6y=84

y= 84/6

y=14

there the speed in still water is 14mph

radiation warms things up temp rises convection currents air circ windy weather

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.