Physics, 06.10.2019 17:10 gonzaleze18

Aprojectile is shot horizontally at 23.4 m/s from the roof of a building 55.0 m tall. (a) determine the time necessary for the projectile to reach the ground below. (b) determine the distance from the base of the building that the projectile lands. (c) determine the horizontal and vertical components of the velocity just before the projectile reaches the ground.

Answers: 2

Show answers

Answers

Answer from: ryliepeloquinf

(a) 3.35 s

The time needed for the projectile to reach the ground depends only on the vertical motion of the projectile, which is a uniformly accelerated motion with constant acceleration

a = g = -9.8 m/s^2

towards the ground.

The initial height of the projectile is

h = 55.0 m

The vertical position of the projectile at time t is

$y = h + \frac{1}{2}at^2$

By requiring y = 0, we find the time t at which the projectile reaches the position y=0, which corresponds to the ground:

$0 = h + \frac{1}{2}at^2\\t=\sqrt{-\frac{2h}{a}}=\sqrt{-\frac{2(55.0 m)}{(-9.8 m/s^2)}}=3.35 s$

(b) 78.4 m

The distance travelled by the projectile from the base of the building to the point it lands depends only on the horizontal motion.

The horizontal motion is a uniform motion with constant velocity -

The horizontal velocity of the projectile is

v_x = 23.4 m/s

the time it takes the projectile to reach the ground is

t = 3.35 s

So, the horizontal distance covered by the projectile is

d=v_x t = (23.4 m/s)(3.35 s)=78.4 m

The motion of the projectile consists of two independent motions:

- Along the horizontal direction, it is a uniform motion, so the horizontal velocity is always constant and it is equal to

v_x = 23.4 m/s

so this value is also the value of the horizontal velocity just before the projectile reaches the ground.

- Along the vertical direction, the motion is acceleration, so the vertical velocity is given by

v_y = u_y +at

where

u_y = 0 is the initial vertical velocity

Using

a = g = -9.8 m/s^2

and

t = 3.35 s

We find the vertical velocity of the projectile just before reaching the ground

v_y = 0 + (-9.8 m/s^2)(3.35 s)=-32.8 m/s

and the negative sign means it points downward.

Answer from: Quest

radiation

explanation:

heat is transmitted by radiation

Answer from: Quest

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me

Another question on Physics

Physics, 22.06.2019 00:30

Aball tossed vertically upward from the ground next to a building passes the bottom of a window 1.8 s after being tossed and passes the top of the window 0.20 s later. the window is 2.0 m high from top to bottom. what was the ball's initial velocity? the unit vector j^ is directed upward. how far is the bottom of the window from the launch position? how high does the ball rise above the launch position?

Answers: 1

Answer

Physics, 22.06.2019 03:00

According to newtons universal law of gravitation, which would change the parh of the ball so it traces out widest curved path possible?

Answers: 1

Answer

Physics, 22.06.2019 18:00

Acid precipitation chemically weathering a 5.0-kg limestone rock . which coukd be the result ?

Answers: 1

Answer

Physics, 22.06.2019 18:20

An object dropped from cliff falls with a constant acceleration of 10 metre per second square find its speed of two seconds after it was dropped