# A high diver jumping off a board (basic force problem)

In summary, the conversation discusses the calculation of the average force exerted on a high diver who jumps off a board 10.0 m above the water and is stopped in 2.30 s. The final velocity of the diver is found to be 14 m/s and the average acceleration is calculated to be 6.08696 m/s^2. However, there is a discrepancy in the answer due to the convention of positive and negative signs in acceleration.

## Homework Statement

A high diver of mass 50.0 kg jumps off a board 10.0 m above the water. If her downward motion is stopped 2.30 s after she enters the water, what average force did the water exert on her?

Fnet=ma
vf2=v02+2ax

## The Attempt at a Solution

First I found the final velocity of the diver when she hits the water

vf2=02+2(9.8)(10)=196

vf=14 m/s

Since she is slowed to a stop in 2.3s the average acceleration would be

14/2.3 = 6.08696

Knowing acceleration and her mass, we can calculate the force.

F=50(6.08696)=304.348

This answer was marked wrong. I'm pretty sure I did everything right. Am I missing something?

Your calculation is correct for the magnitude of the acceleration. Maybe the dumb machine that marked this problem expected a negative sign in front of the acceleration. I say "dumb" because the acceleration is in the "up" direction which is conventionally positive. You may have to ask your teacher for a clarification of this point.

## 1. What is the force that propels a high diver off the diving board?

The force that propels a high diver off the diving board is the force of gravity. This force is constantly pulling the diver towards the center of the Earth, causing them to accelerate towards the ground.

## 2. How does the height of the diving board affect the force on the high diver?

The height of the diving board affects the force on the high diver by increasing the potential energy of the diver as they climb to a higher point. This potential energy is then converted into kinetic energy as the diver jumps off the board.

## 3. Why does a high diver bend their knees before jumping off the diving board?

A high diver bends their knees before jumping off the diving board to increase their potential energy. By bending their knees, they are able to store more energy in their muscles, which can then be released as they push off the board.

## 4. What role does air resistance play in a high dive?

Air resistance plays a significant role in a high dive. As the diver falls through the air, air molecules collide with their body, creating a force that opposes their motion. This force increases as the diver's speed increases, eventually balancing out the force of gravity and causing the diver to reach a terminal velocity.

## 5. How does the angle of entry affect the high diver's splash?

The angle of entry affects the high diver's splash by determining the amount of water the diver displaces upon impact. If the diver enters the water at a steeper angle, they will displace more water and create a larger splash. However, if the diver enters at a shallower angle, the splash will be smaller as less water is displaced.

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