Please try to be clear in your explanation!!
A swimmer bounces straight up from a diving board and falls feet first into a pool. She starts with a velocity of 5.00 m/s, and her takeoff point is 1.50 m above the pool.
(a) How long are her feet in the air?
______seconds
(b) What is her highest point above the board?
________meters
(c) What is her velocity when her feet hit the water?
_________meters/second
THANK YOU!!
Use the 5 kinematic eqns since she has uniform acceleration (gravity). for a, you have how far up she is from landing (displacement), the acceleration (gravity), Vi(5m/s up), and you're solving for time. make sure your signs are correct when you calculate though.
For b, the highest point is at the vertex, use the one kinematic eqn that doesn't involve t, because you don't care about time. At the highest point don't forget that V2 is zero for that one instant.
and for c, you know how far she is from the ground, and use the same equation that disregards time, and make sure your signs are all correct.
umm sry i don't understand, im in just regualr physics and i don't konw what kinematic or any equations are. could you give me the equation or something
To answer these questions, we can use the principles of kinematics. Let's break down each question and explain how to get the answer:
(a) How long are her feet in the air?
To find the time her feet are in the air, we can use the equation of motion:
Δy = v₀t + (1/2)at²
In this case, the swimmer starts with an initial velocity at takeoff (v₀) of 5.00 m/s, the displacement (Δy) is the difference in height between the takeoff point and the pool's surface (1.50 m), and the acceleration (a) is the acceleration due to gravity (-9.81 m/s²).
We want to find the time (t), so we can rearrange the equation as follows:
1/2at² + v₀t - Δy = 0
Using the quadratic formula, t = (-v₀ ± √(v₀² - 4(1/2a)(-Δy))) / (2(1/2a)).
After substituting the values, the positive value for t is the time her feet are in the air.
(b) What is her highest point above the board?
To find the highest point, we need to determine the displacement from the takeoff point to the highest point reached. Since the swimmer's velocity decreases due to gravity, the highest point is reached when the velocity is zero:
v = v₀ + at
At the highest point, v = 0, so we can rearrange the equation to solve for displacement:
Δy = (v₀²) / (2a)
Substituting the values will give us the highest point above the board.
(c) What is her velocity when her feet hit the water?
To find the velocity when her feet hit the water, we can use the equation:
v = v₀ + at
Here, v₀ is the initial velocity (5.00 m/s), a is the acceleration due to gravity (-9.81 m/s²), and t is the time calculated in part (a). Substituting these values in the equation will give us the velocity.
By following the steps and using the provided values, you should be able to calculate the answers to these questions.