What is the velocity of the ball after H height? Considering wind resistance?

In summary: You need to use the differential equation ##m \frac{dv}{dt} = mg - kv^2##.The velocity of the ball when it hits the water can be found using the conservation of energy principle, also known as the work-energy theorem.The velocity of the ball at the bottom of the tank can also be found using the conservation of energy principle, but you will need to consider the energy lost due to drag.In summary, the problem involves finding the velocity of a ball dropped into a water tank from a given height. The equations of F=ma, Fd = (Cd*p*v^2*A)/2, and Fnet=Fd-Fg are relevant and the drag force should be considered. The velocity when
  • #1
TheWhiteKnyt
2
0
I've been trying to figure out this problem for hours my whole group and most of the class is stumped. We understand that we need to relate the equations of F=ma, Fd = (Cd*p*v^2*A)/2, Fnet=Fd-Fg. No data is given. The answer is a V=____ equation. Even just an answer to #1 would be very helpful! Thanks!

1. Homework Statement


A spherical ball of mass m is dropped from a height H above
the surface of a large water tank. The depth of the water below
is D . The ball hits surface of the water and then continues down
into the water tank, eventually coming to rest at the bottom of the
tank. You should assume that air and water resistance are *not*
negligible in this problem.

1. What is the velocity of the ball when it hits the water?

2. What is the velocity of the ball at the moment it hits the bottom of
the tank?

3. Please draw time-aligned graphs of position, velocity, and acceleration of the ball for its
entire trip from the moment it is dropped until the moment it comes to rest at the bottom of the
tank.

Homework Equations



F=ma, Fd = (Cd*p*v^2*A)/2, Fnet=Fd-Fg.

The Attempt at a Solution



All I've got so far is: Fnet = Fg - Fair = mg - kv(t) = ma(t)
 

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  • #2
TheWhiteKnyt said:
I've been trying to figure out this problem for hours my whole group and most of the class is stumped. We understand that we need to relate the equations of F=ma, Fd = (Cd*p*v^2*A)/2, Fnet=Fd-Fg. No data is given. The answer is a V=____ equation. Even just an answer to #1 would be very helpful! Thanks!

1. Homework Statement


A spherical ball of mass m is dropped from a height H above
the surface of a large water tank. The depth of the water below
is D . The ball hits surface of the water and then continues down
into the water tank, eventually coming to rest at the bottom of the
tank. You should assume that air and water resistance are *not*
negligible in this problem.

1. What is the velocity of the ball when it hits the water?

2. What is the velocity of the ball at the moment it hits the bottom of
the tank?

3. Please draw time-aligned graphs of position, velocity, and acceleration of the ball for its
entire trip from the moment it is dropped until the moment it comes to rest at the bottom of the
tank.

Homework Equations



F=ma, Fd = (Cd*p*v^2*A)/2, Fnet=Fd-Fg.

The Attempt at a Solution



All I've got so far is: Fnet = Fg - Fair = mg - kv(t) = ma(t)

According to the problem statement, the drag force on the ball is proportional to velocity squared, so your equation for Fnet needs correcting.

You won't be able to write your equation for v just by doing algebraic manipulations on the various force quantities. You will have to consult with Mr. Calculus for this problem.
 

Related to What is the velocity of the ball after H height? Considering wind resistance?

1. What factors affect the velocity of the ball after reaching a certain height?

The velocity of a ball after reaching a certain height is affected by several factors, including the initial velocity of the ball, the angle at which it was thrown, the gravitational pull, and air resistance or wind resistance.

2. How does air resistance or wind resistance affect the velocity of the ball?

Air resistance or wind resistance acts in the opposite direction of the ball's motion, causing a decrease in velocity. This is because the air molecules exert a force on the ball, slowing it down as it moves through the air.

3. Can the velocity of the ball be calculated accurately when considering wind resistance?

Yes, the velocity of the ball can be calculated accurately when considering wind resistance. However, it may require more complex calculations and/or the use of computer simulations to account for the varying wind conditions.

4. How does the velocity of the ball change as it moves through different wind conditions?

The velocity of the ball will change depending on the direction and speed of the wind. If the wind is blowing in the same direction as the ball's motion, it will increase the velocity of the ball. Conversely, if the wind is blowing in the opposite direction, it will decrease the velocity of the ball.

5. Is there a way to minimize the effect of wind resistance on the velocity of the ball?

Yes, the effect of wind resistance on the velocity of the ball can be minimized by reducing the surface area of the ball, making it more aerodynamic. Additionally, throwing the ball at a higher initial velocity can also help to counteract the effects of wind resistance.

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