Aperson looking out the window of a stationary train notices that raindrops are falling vertically down at a speed of 8.1 m/s relative to the ground. when the train moves at a constant velocity, the raindrops make an angle of 59° when they move past the window, as the drawing shows. how fast is the train moving?

speed of train is 13.48 m/s

Explanation:

given data

raindrop speed = 8.1 m/s

angle = 59°

to find out

How fast is the train moving

solution

we know it make a triangle so

by triangle law we know

tan(θ) =    ...............1

here y is rain speed and x is train speed

so put here all value in equation 1

tan(59) =  

x= 13.48

so speed of train is 13.48 m/s

fgravity=10x10=100n case 1

fgravity=30x20=600n case 2

6 times more

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s