# physics

A 65 kg diver jumps off of a 10.0 m tower.

a. Find the diver's velocity when he hits the water.

b. The diver comes to a stop 2.0 m below the surface. Find the net force exerted by the water.

Ok, im confused, I found velocity which is 14. But for the net force im confused on what we are finding when using this equation below.

For the force, it would be similar to the car acceleration problem, except that to find the deceleration in water, we would use
v1²-v²=2aS
S=distance (2 m)
v1=final velocity =0
v=initial velocity as found above
a=deceleration due to water (negative) including effects of buoyancy and gravity.
and finally
F=ma

1. 👍 0
2. 👎 0
3. 👁 382
1. You're quite right, the deceleration as calculated above accounts for gravity, but the force does not.
From v=14, v1=0, we calculate a=(14²-0²)/2/2m=49
F=ma=65*49=3185 N
On this we have to add the weight of the diver, 65*9.8 to give 3822 N.

As suggested by Drwls, it is simpler to do this all in one step by energy considerations, if that's the topic you are working on in class.

Σ PE+KE at start
= Σ PE+KE+work done
PE=potential energy
KE=kinetic energy

At start:
PE = mgh (h=12 m relative to final position)
KE = 0
At end:
PE = 0
KE = 0
Work done = F*2 metres
Therefore
mgh+0 = 0 + 0 + 2F
F=mgh/2
= 65*9.8*12/2
= 3822 N

1. 👍 0
2. 👎 0
2. bob

1. 👍 0
2. 👎 0

## Similar Questions

1. ### Math

A deep-sea exploring ship is pulling up a diver at the rate of 25 feet per minute. The diver is 200 feet below sea level. How deep was the diver 10 minutes ago?

asked by Mo on October 18, 2016
2. ### Physics

At the local swimming pool, the diving board is elevated h = 7.5 m above the pool surface and overhangs the pool edge by L = 2 m. A diver runs horizontally along the diving board with a speed of v0 = 3.4 m/s and then falls into

asked by Lauren HELP on September 11, 2014
3. ### physics

A 65 kg diver jumps off of a 10.0 m tower. a. Find the diver's velocity when he hits the water. b. The diver comes to a stop 2.0 m below the surface. Find the net force exerted by the water. Ok, im a little confused about this

asked by Heart on December 23, 2009
4. ### College Algebra

A sky diver jumps from a reasonable height above the ground. The air resistance she experiences is proportional to her velocity, and the constant of proportionality is 0.23. It can be shown that the downward velocity of the sky

asked by Melany on July 31, 2015
5. ### math

the path of a cliff diver as he dives into a lake is given by the equation y=-(x-10)power of 2 + 75...where y meters is the divers height above the water and x metres is the horizontal distance travelled by the diver. what is the

asked by sharon on May 3, 2015
1. ### Physics

A sky diver of mass 80.0 ks jumps from a slow-moving aircraft and reaches a terminal speed of 50.0 m/s. a) What is the acceleration of the sky diver when her speed is 30.0 m/s? What is the drag force on the diver when her speed is

asked by Jean on March 1, 2007
2. ### Physics

A 86.0 kg diver falls from rest into a swimming pool from a height of 6.3 m. It takes 1.44 s for the diver to stop after entering the water. Find the magnitude of the average net force exerted on the diver during that time.

asked by Bob on December 6, 2011
3. ### Algebra 1

A diver jumps from a platform 25 feet above the surface of the water. The diver's height above the water is given by the equation h(t)=-16t^2+14.5t + 25, where t is the time, in seconds, after the diver jumps. A.)When will the

asked by Caitlyn on November 30, 2017
4. ### physics

A 755 N diver drops from a board 10.0m above the water's surface.Find the diver's speed 5.00 m above the water's surface. Then find the diver's speedjust before striking the water.

asked by hannah on November 5, 2014
5. ### Physics

A 50.0 kg diver steps off a diving board and drops straight down into the water. The net force when in the water is an upward 1450 N. If the diver comes to rest 5.0 m below the water's surface, what is the total distance between

asked by Becky on March 9, 2011
6. ### Physics

A high diver of mass 70 kg jumps off a diving board and enters the water with the speed of 10 m/s the average upward resistance force of water exerts on the diver is 200 N. How far in the water will the diver travel before coming

asked by Anonymous on June 16, 2014