E) the time it takes the car to reach 20.0ms-1

An object moving due to gravity can be described by the motion equation y=y0+v0t−12gt2, where t is time, y is the height at tha

Lynna [10]

Answer: 6.45 s

Explanation:

We have the following equation:

$y=y_{o}+V_{o}t-\frac{1}{2}gt^{2}$ (1)

Where:

$y=0$ is the height when the rock hits the ground

$y_{o}=75 m$ the height at the edge of the cilff

$V_{o}=20 m/s$ the initial velocity

$g=9.8 m/s^{2}$ acceleration due gravity

$t$ time

$0=75 m+(20 m/s)t-(4.9 m/s^{2})t^{2}$ (2)

Rearranging the equation:

$-(4.9 m/s^{2})t^{2} + (20 m/s)t + 75 m=0$ (3)

At this point we have a quadratic equation of the form $at^{2}+bt+c=0$ , and we have to use the quadratic formula if we want to find $t$ :

$t=\frac{-b\pm\sqrt{b^{2}-4ac}}{2a}$ (4)

Where $a=-4.9$ , $b=20$ , $c=75$

Substituting the known values and choosing the positive result of the equation:

$t=\frac{-20\pm\sqrt{20^{2}-4(-4.9)(75)}}{2(-4.9)}$ (5)

$t=6.453 s$ This is the time it takes to the rock to hit the ground

8 0

3 years ago

Porque alguno satélites de telecomunicaciones puede permanecer en una orbita geoestacionaria

agasfer [191]

<span>Es para la comodidad del cliente. <span>Si el satélite no estaba parado
en el cielo, entonces el cliente tendría que seguir moviendo su plato
para seguir el satélite.</span></span>

4 0

3 years ago

Randall is able to paddle his canoe at 2.0 m/s in still water. He drops the canoe into a river which is flowing north at 1.5 m/s

Alecsey [184]

South I’msure he travels south

4 0

2 years ago

To what circuit element is an ideal capacitor equivalent in circuits for which the currents and voltages are constant with time?

Vanyuwa [196]

Explanation:

Since the current flowing through an ideal capacitor is described by equation:

$i_{C}=C\frac{dV}{dt}$

for voltage across the capacitor constant with time the current is:

$i_{C}=\frac{d(Constant)}{dt}=0$

Open switch has this characteristics (Constant voltage and zero current).

3 0

3 years ago

Superman is off to visit Lois lane. He sees he's late and increases his flying speed. I know he defies the laws of physics anywa

mario62 [17]

Answer:

975 m/s^2

Explanation:

The formula for rate of acceleration is

(Final velocity - intial velocity)/ time taken

If you plug in your data you will get 975 m/s^2

(1600 m/s -1210 m/s )/.4 s = 975 m^2

7 0

3 years ago

E) the time it takes the car to reach 20.0ms-1​

E) the time it takes the car to reach 20.0ms-1