Anyone please help me with this question ASAP

A stone is thrown vertically upward with a speed of 20.0 m/s. (a) How fast is it moving when it reaches 12.0 m? (b) How long is

kaheart [24]

(a) How fast is it moving when it reaches 12.0 m?
To determine the velocity as it reaches 12.0 m, we use one of the kinematic equations,
V^2 = Vo^2 + 2gh
where Vo = 20 m/s. 
 g = -9.8 m/s^2 
 h = 12.0 m. 
V^2 = 20^2 + 2(-9.8)(12.0)
V^2 = 164.8
V = 12.84 m/s

(b) How long is required to reach this height?
To determine the maximum height, we use the same equation we used above,
V^2 = Vo^2 + 2gh
where Vo = 20 m/s.
g = -9.8 m/s^2
V = 0 (since at the maximum height velocity is zero)
0^2 = 20^2 + 2(-9.8)h
h = 20.41 m

(c) Why are there two answers for (b)?
There are two answers for b because it would travel a distance up and travel a distance down.

5 0

3 years ago

Read 2 more answers

Express the length of a marathon run of 26 mi 385 yd in meters. Answer in units of m.

hjlf

Answer:

1 mi = 5280 ft * 12 in/ft = 63360 in

A convenient conversion factor (to remember) is 1 m = 39.37 in

63360 in / (39.37 in / m) = 1609.3 m

26 mi + 285 m = 26 * 1609.3 + 385 = 42,228 m

6 0

3 years ago

The interaction between two optical and perceptual phenomena makes moving pictures possible. the persistence of vision provides

Marina86 [1]

It seems that you have missed the necessary options for us to answer this question, but anyway here are the answers. The interaction between two optical and perceptual phenomena makes moving pictures possible. the persistence of vision provides the illusion of SUCCESSION while the phi phenomenon provides the illusion of MOVEMENT. Hope this helps.

8 0

4 years ago

A heat recovery system (HRS) is used to conserve heat from the surroundings and supply it to the Mars Rover. The HRS fluid loop

Annette [7]

Answer: Volume of Freon = 12.23. $10^{3}$ L

Explanation: First, the temperatures have to be in the same unit, so all the tmeperatures is transformed into Kelvin:

T₁ = 192K

T₂ = $\frac{5}{9}$ . (F - 32)+273.15

T₂ = $\frac{5}{9}$ . (- 65 - 32)+273.15

T₂ = 219.26K.

Second, BTU is an unit of energy. It can be transformed into Joules by the relation 1BTU = 1055.06J.

Q = 1055.06 . 46.9 = 49482.314J

The letter Q represents Heat and is calculated as Q = m.Cp.ΔT, where:

m is mass of the element;

Cp is the heat capacity specific for each element;

ΔT is the difference between the final and initial temperature;

Third, it will be needed the properties of the Freon:

Freon (CF2Cl2) = 120.91g/mol; Cp = 74J/mol.K; ρ = 1.49kg/m³

Fourth, we calculate the mass of Freon necessary for the remove of 46.9BTU of energy from the system:

Q = m.Cp.ΔT

m= $\frac{Q}{c(T-T_{0} )}$

m = $\frac{49482.314}{74(219.26-192)}$

m = 18228.214g or m=18.228Kg

Fifth, using the density of Freon, Volume can be found

ρ = $\frac{m}{V}$

V = m / ρ

V = 18.228 / 1.49

V = 12.23m³

As SI for density is Kg/m³, the volume found is in m³.

Cubic meters is related to Liters as the following: 1m³=1000l.

So, volume of Freon = 12.23. $10^{3}$ L

The volume of Freon needed is 12.23. $10^{3}$ L.

7 0

3 years ago

Two coherent sources of radio waves, A and B, are 5.00 meters apart. Each source emits waves with wavelength 6.00 meters. Consid

Korolek [52]

Answer:

a

$z= 2.5 \ m$

b

$z = (1 \ m , 4 \ m )$

Explanation:

From the question we are told that

Their distance apart is $d = 5.00 \ m$

The wavelength of each source wave $\lambda = 6.0 \ m$

Let the distance from source A where the construct interference occurred be z

Generally the path difference for constructive interference is

$z - (d-z) = m \lambda$

Now given that we are considering just the straight line (i.e points along the line connecting the two sources ) then the order of the maxima m = 0

so

$z - (5-z) = 0$

=> $2 z - 5 = 0$

=> $z= 2.5 \ m$

Generally the path difference for destructive interference is

$|z-(d-z)| = (2m + 1)\frac{\lambda}{2}$

=> $|2z - d |= (0 + 1)\frac{\lambda}{2}$

=> $|2z - d| =\frac{\lambda}{2}$

substituting values

$|2z - 5| =\frac{6}{2}$

=> $z = \frac{5 \pm 3}{2}$

So

$z = \frac{5 + 3}{2}$

$z = 4\ m$

and

$z = \frac{ 5 -3 }{2}$

=> $z = 1 \ m$

=> $z = (1 \ m , 4 \ m )$

7 0

3 years ago