Physics
posted by Lilian .
From the top of a cliff with 80 m height a stone is thrown vertically and finally hit the surface of ocean.
Initial velocity of stone is 40 m/s.
Find:
(a) time to reach to max height.
(b) how high goes from surface of ocean?
(c) what is velocity of stone 2 second after thrown?
(d) what is velocity of stone at 20 meters above ocean?
(e) total traveled time?
(f) at what times velocity is 10 m/s?
(g) what is velocity of ball 40 m above ocean?
(h) what is velocity of ball after 6 second from thrown?
(i) at what height from the ocean surface velocity is 50 m/s?
(j) what is velocity of stone just before hit the ocean surface?
I calculated that:
(a) tmax = 4.08 s
(b) ytotal = 161.6 m
(c) vy = 20.4 m/s
(d) vy = 20.4 m/s
(e) ttotal = 9.83 sec
(f) t1 = 3.06 sec ; t2 = 5.1 sec
How would you exactly find g~j? :/
I suppose the variables confuses me a bit.

Physics 
Henry
a. Tr = Vo/g = 40/9.8 = 4.08 s. = Rise
time.
b. h = ho + (V^2Vo^2)/2g
h = 80 + (0(40^2))/19.6 = 161.6 m.
Above gnd.
c. V = Vo + g*t = 40  9.8*2 = 20.4 m/s.
d. V*2 = Vo^2 + 2g*(h20)
V^2 = 0 + 19.6*(161.620) = 2775.36
V = 52.7 m/s.
e. h = 4.9t^2 = 161.6 m.
4.9*t^2 = 161.6
t^2 = 32.979
Tf = 5.74 s. = Fall time.
Tr+Tf = 4.08 + 5.74 = 9.82 s. = Total
time traveled.
f. V = Vo+g*t = 40  9.8*t = 10 m/s.
9.8t = 1040 = 30
t = 3.06 s.
g. Same procedure as d.
h. V = Vo+g*t = 40  9.8*6 = 18.8 m/s.
The negative sign means the stone is falling.
i. h = ho  (V^2Vo^2)/2g
h = 161.6  (50^20)/19.6 = 34 m.
j. V=Vo + g*Tf = 0 + 9.8*5.74=56.3 m/s
Respond to this Question
Similar Questions

Calculus/Physics
A stone is thrown from a cliff top with an upward velocity of 20 m/s. It takes 7 seconds for the stone to hit the ground at the bottom of the cliff. How high is the cliff? 
Physics
A girl throws a stone form the top of a building with an initial velocity of 20.0 m/s upward. The building is 50.0 m high and the stone just misses the edge of the roof on its way down. Draw a v vs t graph, find time needed for stone … 
civil engineering
A stone (on the edge of the roof) thrown from the top of a building is given an initial velocity of 20.0 m/s straight upward. The building is 50.0 m high, as shown in Fig. 4. Using tA = 0 as the time the stone leaves the throwerâ€™s … 
Physics
A stone is thrown from the edge of a cliff into the ocean below. It is thrown somewhat upward, but mostly outward. The stone has a mass of 2.0kg and is thrown with a speed of 10m/s from an initial height of 5.0m above the ocean. A. … 
Physics
A stone is thrown from the edge of a cliff into the ocean below. It is thrown somewhat upward, but mostly outward. The stone has a mass of 2.0kg and is thrown with a speed of 10m/s from an initial height of 5.0m above the ocean. A. … 
physics
A stone is thrown horizontally outward from the top of a bridge, the stone is released 19.6meter above the street below.the initial velocity of the stone is 5.0m/s.determine the (a)total time that the stone is in the air (b)magnitude … 
Physical
At t = 0 s time a stone is thrown from the top of a cliff above a lake. Another stone is thrown down from the same point , 1.6 s later , with a initial velocity of 32.0 m / s. The two stones hit the water in one instant. Determine … 
physics
a stone is thrown vertically upward an initial velocity of 12m/s from the top of a building . it takes 3.4s for the stone to hit the ground a. find the height of the building b. find the maximum height that the stone will reach c. … 
PHYSICS
A stone thrown from the top of a building is given an initial velocity of 40.0 m/s straight upward. The building is 70.0m high, and the stone just misses the edge of the roof on its way down, determine (A) The time at which the stone … 
SCIENCE
A stone thrown from the top of a building is given an initial velocity of 40.0 m/s straight upward. The building is 70.0m high, and the stone just misses the edge of the roof on its way down, determine (A) The time at which the stone …