Physics, 25.07.2019 14:00 QueenBlumple4443

Astone is dropped from the upper observation deck of a tower, 750 m above the ground. (assume g = 9.8 m/s2.) (a) find the distance (in meters) of the stone above ground level at time t. h(t) = −4.9t2+750 (b) how long does it take the stone to reach the ground? (round your answer to two decimal places.) 12.37 s (c) with what velocity does it strike the ground? (round your answer to one decimal place.) -121.2 m/s (d) if the stone is thrown downward with a speed of 6 m/s, how long does it take to reach the ground? (round your answer to two decimal places.)

Answers: 1

Show answers

Answers

Answer from: zitterkoph

(a) The stone moves by uniform accelerated motion, with constant acceleration g=9.81 m/s^2

directed downwards, and its initial vertical position at time t=0 is 750 m. So, the vertical position (in meters) at any time t can be written as
$y(t)= y_0 - \frac{1}{2}gt^2= 750 - 4.9 t^2$

(b) The time the stone takes to reach the ground is the time at which the vertical position of the stone becomes zero: y(t)=0. So, we can write
750-4.9 t^2 = 0

from which we find the time t after which the stone reaches the ground:
$t= \sqrt{\frac{750 m}{4.9 m/s^2 }}= 12.37 s$

(c) The velocity of the stone at time t can be written as
v(t) = -gt

because it is an accelerated motion with initial speed zero. Substituting t=12.37 s, we find the final velocity of the stone:
v(12.37 s)=-(9.81 m/s^2)(12.37 s)=-121.3 m/s

v(12.37 s)=-(9.81 m/s^2)(12.37 s)=-121.3 m/s

(d) if the stone has an initial velocity of v_0 = 6 m/s

, then its law of motion would be
$y(t)=y_0 - v_0t - \frac{1}{2}gt^2$
and we can find the time it needs to reach the ground by requiring again y(t)=0:
0=750 - 6t - 4.9 t^2

which has two solutions: one is negative so we neglect it, while the second one is t=11.78 s, so this is the time after which the stone reaches the ground.

Answer from: rileybaby34

a) $\rm y(t) = 750-4.9t^2$

b) t = 12.37 sec

c) v = -121.34 m/sec

d) t = 11.78 sec

Given :

Upper observation deck of a tower is 750 m above the ground.

Solution :

a) The vertical position at any time t is given by,

$\rm y(t) = y_0 - \dfrac{1}{2}gt^2$

At t = 0 , y = 750 m

$\rm y(t) = 750 - \dfrac{1}{2}\times 9.81\times t^2$

$\rm y(t) = 750-4.9t^2$ --- (1)

b) The stone is reached to the ground that is, y(t) = 0

So, from equation (1) we get

$\rm t = \sqrt{\dfrac{750}{4.9}}$

t = 12.37 sec

c) Velocity when it strike the ground is given by,

v = u - gt

here initial velocity u = 0, therefore

$\rm v = - 9.81 \times 12.37$

v = - 121.34 m/sec

d) In this case given that initial velocity is 6 m/sec, therefore

$\rm y(t) = y_0 - ut-\dfrac{1}{2}gt^2$ ---- (2)

here stone is reached to the ground so y(t) = 0. From equation (2) we get,

$\rm 0 = 750-(6\times t) -\dfrac{1}{2}\times 9.81 \times t^2$

$\rm 4.9t^2 + 6t -750 = 0$

By solving the above equation we get t = 11.78 sec.

For more information, refer the link given below

link

Answer from: Quest

“foliation in geology refers to repetitive layering in metamorphic rocks. each layer can be as thin as a sheet of paper, or over a meter in thickness. the word comes from the latin folium, meaning "leaf", and refers to the sheet-like planar structure. “i found this on google i hope it you

Answer from: Quest

It's have to be 12 or idk

Another question on Physics

Physics, 22.06.2019 08:40

The system is released from rest with the cable taut, and the homogeneous cylinder does not slip on the rough incline. determine the angular acceleration of the cylinder and the minimum coeffi cient s of friction for which the cylinder will not slip.

Answers: 2

Answer

Physics, 22.06.2019 10:30

What is the speed of an object at a given moment?

Answers: 3

Answer

Physics, 22.06.2019 14:40

The experiment done in lab is repeated, using a ball that has unknown mass m. you plot your data in the form of f 2 versus m/l, with f in rev/s, m in kg, and l in m. your data falls close to a straight line that has slope 3.19 m/(kg · s2). use g = 9.80 m/s2 and calculate the mass m of the ball.

Answers: 1

Answer

Physics, 23.06.2019 01:00

What happens when the number of protons in an atom changes

Answers: 1

Answer

You know the right answer?

Astone is dropped from the upper observation deck of a tower, 750 m above the ground. (assume g = 9....

Questions