Force of water on falling bag

In summary, the force of water on a falling bag is determined by its weight and velocity, as well as factors such as shape, size, density, viscosity, and impact height and surface. To calculate the force, one can use the formula F = m x a or F = 0.5 x p x v^2 x A. The force can be reduced by adjusting these factors and studying it has practical applications in various industries and understanding the impact of water on structures and materials.
  • #1
Brittykitty
81
0
At an altitude of 315 m above a lake, a hot-air balloon pilot drops a 2.50 kg sandbag. If the bag comes to a stop 4.50 m below the surface of the lake, what force was applied by the water on it?

I was thinking v= 2.50kg x 9.81km/h= 24.525m/s
i can't remember how to get the force
 
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  • #2


Like I replied in your other thread with the same problem, use the law of conservation of energy.

Work=force*distance.
 
  • #3
of the water on the bag

I would approach this problem by using the principles of Newton's laws of motion and fluid dynamics. To determine the force applied by the water on the falling bag, we need to consider the change in momentum of the bag as it falls into the water.

First, we can calculate the initial velocity of the bag using the given altitude of 315 m and assuming no air resistance. Using the equation v^2 = u^2 + 2as, where v is the final velocity (0 m/s), u is the initial velocity, a is the acceleration due to gravity (9.81 m/s^2), and s is the distance (315 m), we can solve for u to get an initial velocity of 24.9 m/s.

Next, we can use the equation p = mv, where p is momentum, m is mass (2.50 kg), and v is velocity, to calculate the initial momentum of the bag. This gives us a value of 62.25 kg m/s.

As the bag falls into the water, it experiences a change in momentum due to the force of the water pushing against it. Using the equation F = dp/dt, where F is force, dp is the change in momentum, and dt is the change in time, we can calculate the force applied by the water on the bag.

To do this, we need to determine the change in time (dt) for the bag to come to a stop. We can use the equation v = u + at, where v is the final velocity (0 m/s), u is the initial velocity (24.9 m/s), a is the acceleration due to gravity (9.81 m/s^2), and t is the time. Solving for t gives us a value of 2.54 seconds.

Substituting these values into the equation F = dp/dt, we get F = (0 - 62.25 kg m/s) / 2.54 s = -24.5 N. This negative value indicates that the force of the water on the bag is in the opposite direction to its initial momentum, which makes sense as the water is pushing against the bag to slow it down.

Therefore, the force applied by the water on the falling bag is approximately 24.5 Newtons.
 

1. What is the force of water on a falling bag?

The force of water on a falling bag is determined by the weight of the water and the velocity at which it hits the bag. This force is also affected by the shape and size of the bag, as well as the density and viscosity of the water.

2. How do you calculate the force of water on a falling bag?

To calculate the force of water on a falling bag, you can use the formula F = m x a, where F is the force, m is the mass of the water, and a is the acceleration of the water as it hits the bag. You can also use the formula F = 0.5 x p x v^2 x A, where p is the density of the water, v is the velocity of the water, and A is the surface area of the bag.

3. What factors affect the force of water on a falling bag?

The force of water on a falling bag is affected by several factors, including the weight and velocity of the water, the shape and size of the bag, and the density and viscosity of the water. Additionally, the height from which the bag is dropped and the surface on which it lands can also impact the force of the water.

4. How can the force of water on a falling bag be reduced?

The force of water on a falling bag can be reduced by decreasing the weight and velocity of the water, choosing a bag with a shape and size that minimizes the impact, and using water with a lower density and viscosity. Additionally, dropping the bag from a lower height or onto a soft surface can also help reduce the force of the water.

5. What are the practical applications of studying the force of water on a falling bag?

Studying the force of water on a falling bag can have practical applications in various industries, such as engineering, construction, and design. It can also be useful in understanding the impact of water on structures and materials in natural disasters like floods and hurricanes. Additionally, this knowledge can be applied in creating more efficient and durable products, such as water-resistant bags and containers.

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