Please check my answers!!
1. A 75 kg. man steps off the end of a diving board, and hits the water at 7.7 m/s. Ignoring air resistance, what was the mans PE (potential energy) right before he stepped off the diving board?
I got 2223.375 Joules after Damon helped me...am I right?
2. How high is the diving board?
I got 29.645 meters after Damon helped me.
Did I make any mistakes???
PLEASE someone help!!!
noe, 2223 Joules is right
bUT
m g h = 2223
75 * 9.81 * h = 2223
h = 3.02 meters
To check your answers, let's calculate them step by step:
1. To find the potential energy (PE) of the man before he stepped off the diving board, we can use the equation PE = m*g*h, where m is the mass of the man (75 kg), g is the acceleration due to gravity (9.8 m/s^2), and h is the height.
PE = 75 kg * 9.8 m/s^2 * h
Since the man hits the water with a resultant velocity (v) of 7.7 m/s, his initial potential energy (PE) is equal to his final kinetic energy (KE).
KE = (1/2) * m * v^2
Substituting the values:
(1/2) * 75 kg * (7.7 m/s)^2 = 1880.775 Joules
Therefore, the man's potential energy right before he stepped off the diving board was approximately 1880.775 Joules, not 2223.375 Joules as you mentioned. So, there seems to be a mistake in your calculation.
2. To find the height of the diving board, we can rearrange the potential energy equation as follows:
PE = m * g * h => h = PE / (m * g)
Plugging in the values:
h = 1880.775 Joules / (75 kg * 9.8 m/s^2) = 2.416 meters
Therefore, the diving board's height is approximately 2.416 meters, not 29.645 meters as you mentioned. So, there seems to be a mistake in your calculation.
In summary, your calculated answers were not correct. The potential energy right before the man stepped off the diving board was approximately 1880.775 Joules, and the height of the diving board is approximately 2.416 meters.