Q) M1 = 30 kg M2 = 40 kg d = 60 cm. Find force

does anyone know or what?

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray

3. dark matter

empty space could also be a simple vacuum