Because light travels in a straight line and casts a shadow, Isaac Newton hypothesized that light is

a projectile whose masss is 10g is fired directly upward from ground level with an initial velocity of 1000m/s neglecting the ef

sammy [17]

Answer:

The speed of the projectile when it impacts the ground is 1000 m/s

Explanation:

Vertical Launch

When an object is launched vertically and upwards it starts to move at an initial speed vo, then the acceleration of gravity makes that speed to reduce until it reaches 0. The object has reached its maximum height. Then, it starts to move downwards in free fall, with initial speed zero and gradually increasing it until it reaches the ground level. We will demonstrate that the speed it has when impacts the ground is the same (and opposite) as the initial speed vo.

The speed when the object is moving upwards is given by

$v_f=v_o-g.t$

The time it takes to reach the maximum height is when vf=0, i.e.

$0=v_o-g.t$

solving for t

$\displaystyle t=\frac{v_o}{g}$

The maximum height reached is

$\displaystyle y=\frac{gt^2}{2}=\frac{v_o^2}{2g}$

Then, the object starts to fall. The object's height is given by

$\displaystyle y=\frac{v_o^2}{2g}-\frac{gt'^2}{2}$

where t' is the time the object has traveled downwards. The height will be 0 again when

$\displaystyle \frac{v_o^2}{2g}=\frac{gt'^2}{2}$

Solving for t'

$\displaystyle t'=\frac{v_o}{g}$

We can see the time it takes to reach the maximum height is the same it takes to return to ground level. Of course, the speed when it happens is

$v_f=g.t'=v_o$

Thus, the speed of the projectile when it impacts the ground is 1000 m/s

4 0

4 years ago

The deck of a bridge is suspended 235 feet above a river. If a pebble falls off the side of the bridge, the height, in feet, of

Aleks04 [339]

Answer:

(a) 1, average velocity = -65.6 m/s

2, average velocity = -64.8 m/s

3, average velocity = -64.16 m/s

(b) The instantaneous velocity is -96 m/s

Explanation:

(a)

Average velocity is given by;

$y(t_2,t_1) = \frac{y(t_2) - y(t_1)}{t_2-t_1}$

(1)

$y(2.1,2) = \frac{(235-16*2.1^2) - (235-16*2^2)}{2.1-2}\\\\ y(2.1,2) = -65.6 \ m/s$

(2)

$y(2.05,2) = \frac{(235-16*2.05^2) - (235-16*2^2)}{2.05-2}\\\\ y(2.05,2) = -64.8 \ m/s$

(3)

$y(2.01,2) = \frac{(235-16*2.01^2) - (235-16*2^2)}{2.01-2}\\\\ y(2.01,2) = -64.16 \ m/s$

b. y = 235 - 16t²

The instantaneous velocity is given by;

v = dy /dt

dy / dt = -32t

when t = 3 s

v = -32(3)

v = -96 m/s

5 0

4 years ago

Kik wants to cook popcorn on the stove. What type of energy will she be using

Y_Kistochka [10]

Electrical and thermal

6 0

3 years ago

Read 2 more answers

What is this question

Elena L [17]

Answer:

True

Explanation:

Hope this Helps!

:)

7 0

3 years ago

PLZ HELP! Which is NOT an example of a longitudinal wave?

LenaWriter [7]

The 1st example is NOT a longitudinal wave

Explanation:

Waves are periodic disturbance of the space that travel carrying energy but not matter.

Depending on their vibration, waves are classified into two types:

Transverse waves: in transverse waves, the vibration of the wave occurs in a direction perpendicular to the direction of propagation of the wave. Examples of transverse waves are electromagnetic waves.
Longitudinal waves: in longitudinal waves, the vibration of the wave occurs in a direction parallel to the direction of propagation of the wave (back and forth), creating regions of higher particle density (compressions) and lower particle density (rarefactions). Examples of longitudinal waves are sound waves.

In this problem we have four options given:

The first picture represents a transverse wave, because the vibration of the robe is up and down, while the wave propagates on the left-right direction
The second picture represents a sound wave, which is a longitudinal wave
The 3rd picture represents a longitudinal wave, since the vibration of the slinky is back and forth along the direction of propagation
The 4th picture also represents a sound wave, which is longitudinal

Therefore, the only wave which is not longitudinal is the one in the 1st picture.

Learn more about waves:

brainly.com/question/5354733

brainly.com/question/9077368

#LearnwithBrainly

7 0

4 years ago