PHysics Problem, due tomorrow, ? [50 points]?

Question

guyz, i have this problems.. due tomorrow, pls help me pls.. thank you so much

1. A Russian Balloonist floating at an altitude of 150m accidentally drops his samovar & starts to ascend at the constant velocity of 1.2m/s. How high will the balloons be when the samovar reaches the ground?

2. An orangutan throws a coconut vertically upward at the foot of a cliff 40m high while his make simultaneously drops another coconut from the top of the cliff. The two coconuts collide at an altitude of 20m. What was the initial velocity of the coconut that was thrown upward?

3. A ball is thrown at 20m/s from the roof of a building 25m high at an angle of 30o below the horizontal. At what height above the ground will the ball strike the side of another building 20m away from the first?

Answer 1

1. Was he moving when he dropped it? If not:

s=150m

a=9.8

s=0.5at^2

300=9.8t^2

t=5.5328.....sec

moving at 1.2m/s

therefore

s=vt

s=6.64m upwards

He is at 156.64m when it reaches the ground

2.They collide at 20m, ie in the middle

for the coconut at the top

s=20

a=9.8

v^2 = u^2 + 2as

v = sqrt(392)

when they make contact

v = u+at

sqrt(392) = 9.8t

t = 2.0203.....sec

therefore the one at the bottom must have covered 20m in 2.0203...sec

v=s/t

v=9.90m/s (3sf)

3.

Horizontal component 20cos30

Vertical component 20sin30

s=20m

v=20cos30

v=s/t

t=s/v

t=1.1547....sec

u=20sin30m/s

t=1.1547....sec

a=-9.8m/s/s

s=ut+0.5at^2

s=5.01m

It will move up 5.01m

Therefore it will hit the building at 30.01m

Answer 2

1)

t = sqrt(2h/g) = sqrt(2*150/9.8) = 5.5338 sec

1.2m/s * 5.5338s = 6.6394 meters

Answer 3

1) 150=1/2 x 9.8 x t^2

t=5.53

S=150+1.2 x5.53

s=156.6 m

2) Ball from top

20 = 1/2 x 9.8 x t^2

t=2.02

Bottom ball

20= u x 2.02 - 1/2 x 9.8 x 2.02^2

u=17.8

3) 20 x cos 30 = horizontal velocity

20/ (20 x cos 30) = 2/rt(3) seconds

S=-25+20xsin30 x 2/rt(3) + 1/2 x 9.8 x 2^2/rt(3)^2

S=-25 + 20/rt(3) + 4.9 x 4/3

Answer 4

3.  

      Vy = 20sin30 = 10

      Vx = 20cos30 = 17.3

      dx = 20

      dy = ?

      dy = Vyt + (1/2)(-9.8)t^2

      dy = 10t -4.9t^2

     dx = Vxt

     20 = 17.32t

    20/17.32 = t

    1.15 = t

     dy = 10(1.15) - 4.9(1.15)^2

     dy = 5.01975 m

      

    h = 25 + dy = 30.01 m