A

A student on a tower 49 m height drops a stone. One second later he throws a second stone after the first. They both hit the gro

ohaa [14]

By applying the second equation of motion, the speed at which he threw the second stone is equal to 12.10 m/s.

<h3>How to determine the speed?</h3>

First of all, we would calculate the time taken by the first stone to reach a height of 49 meters by applying the second equation of motion as follows:

S = ut + ½gt²

49 = 0(t) + ½ × 9.8 × t²

49 = 4.9t²

t² = 49/4.9

t = √10

t = 3.16 seconds.

Now, we can determine the speed at which he threw the second stone:

<u>Note:</u> Time = 3.16 - 1 = 2.16 seconds.

S = ut + ½gt²

49 = u(2.16) + ½ × 9.8 × 2.16²

49 = 2.16u + 22.86

2.16u = 49 - 22.86

u = 26.14/2.16

u = 12.10 m/s.

Read more on initial speed here: brainly.com/question/19365526

#SPJ1

6 0

2 years ago

Why malleability is a useful property

Rom4ik [11]

Malleability is a useful property because it allows many products to be made in manufacturing.

4 0

3 years ago

An energy plant produces an output potential of 1500 kV and serves a city 143 km away. A high-voltage transmission line carries

jekas [21]

Answer:

2123.55 $/hr

Explanation:

Given parameters are:

$V_{plant} = 1500$ KV

L = 143 km

I = 500 A

$\rho = 2.4$ $\Omega / km$

So, we will find the voltage potential provided for the city as:

$V_{wire} =IR = I\rho L = 1500*2.4*143 = 514.8$ kV

$V_{city} = V_{plant}- V_{wire} = 1500-514.8 = 985.2$ kV

Then, we will find dissipated power because of the resistive loss on the transmission line as:

$P = I^2R = I^2\rho L=500^2*2.4*143 = 8.58*10^7$ W

Since the charge of plant is not given for electric energy, let's assume it randomly as $x = \frac{\dollar 0.081}{kW.hr}$

Then, we will find the price of energy transmitted to the city as:

$Cost = P * x = 8.58*10^7 * 0.081 * 0.001 = 6949.8$ $/hr

To calculate money per hour saved by increasing the electric potential of the power plant:

Finally,

$I_{new} = P/V_{new} = I/1.2\\P_{new} = I_{new}^2R_{wire}\\Cost = P_{new}/1.44=6949.8/1.44 = 4826.25$ $/hr

The amount of money saved per hour = $6949.8 - 6949.8/1.44 = 2123.55$ $/hr

Note: For different value of the price of energy, it just can be substituted in the equations above, and proper result can be found accordingly.

3 0

3 years ago

The principle of horizontality is based on the observation that sediment usually accumulates in layers. How will you describe th

N76 [4]

The implication is that tilted sedimentary layers observed to day mist have been subjected to tectonic forces

8 0

3 years ago

One way to force air into an unconscious person's lungs is to squeeze on a balloon appropriately connected to the subject. What

frozen [14]

Answer:

The force that you must exert on the balloon is 1.96 N

Explanation:

Given;

height of water, h = 4.00 cm = 4 x 10⁻² m

effective area, A = 50.0 cm² = 50 x 10⁻⁴ m²

density of water, ρ = 1 x 10³ kg/m³

Gauge pressure of the balloon is calculated as;

P = ρgh

where;

ρ is density of water

g is acceleration due to gravity

h is height of water

P = 1 x 10³ x 9.8 x 4 x 10⁻²

P = 392 N/m²

The force exerted on the balloon is calculated as;

F = PA

where;

P is pressure of the balloon

A is the effective area

F = 392 x 50 x 10⁻⁴

F = 1.96 N

Therefore, the force that you must exert on the balloon is 1.96 N

3 0

4 years ago