Marcus throws a ball into the air at a speed of 15m/s. how high does it go? how long doesit take to return to marcus' hand?

height=11.46m

time=3s

Explanation:

Hello!

To solve this problem we must consider the following.

1. The maximum distance traveled upwards corresponds to the moment when the final speed is zero.

2. The ball thrown by marcus has the effect of a constant downward acceleration called gravity (g = 9.81m / s), therefore we can use the equation that describes the movement of a body when it has constant acceleration

where

Vf = final speed

=0M/S

Vo = Initial speed

=15M/S

g=gravity=-9.81m/s^2

Y = displacement

solving

Y=11.46m

3.To calculate the time it takes for the ball to return to Marcus is the sum of the time it takes to go up plus the time it takes to go down.

for the time it takes for the ball to go up we use the following equation

Vf=Vo+a.t                                    

solving for time

Vf=0m/S

Vo=15m/s

g=gravity=-9.81m/s^2

4.for the time it takes to go down, we must take into account that we already know the distance, the gravity and that the initial velocity is 0, we use the following equation

where

y=displacement=11.46M

Vo=0m/s

g=gravity=-9.81m/s^2

t=time

solving for time

t=1.53s

5.  finally we add the time it takes for the ball to go up and down

T=1.53+1.53=3s

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