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Novosadov [1.4K]
2 years ago
9

A boy steps off the end of a 3.00 m high diving board and drops to the water below. Using 9.8 m/s2 as acceleration due to earth'

s gravity, how many seconds does it take for him to reach the water? Only enter the number, not the units.
Physics
1 answer:
Novay_Z [31]2 years ago
5 0

Answer:

t = 0.78 s

Explanation:

Given that,

The height of a diving board, h = 3 m

We need to find the time it take for him to reach the water. Let the time is t./

Using second equation of motion as follows :

h=ut+\dfrac{1}{2}at^2

u is initial velocity, u = 0 and a = g

So,

h=\dfrac{1}{2}gt^2\\\\t=\sqrt{\dfrac{2h}{g}} \\\\t=\sqrt{\dfrac{2\cdot3}{9.8}}\\\\t=0.78\ s

So, it will take 0.78 seconds to reach the water.

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On the Moon's surface, lunar astronauts placed a corner reflector, off which a laser beam is periodically reflected. The distanc
dimulka [17.4K]

Answer:

4.88 x 10∧-8 sec

Explanation:

7 0
3 years ago
You are trying to overhear a juicy conversation, but from your distance of 20.0 m , it sounds like only an average whisper of 30
12345 [234]

Answer:

r₂ = 0.2 m

Explanation:

given,

distance = 20 m

sound of average whisper = 30 dB

distance moved closer = ?

new frequency = 80 dB

using formula

\beta = 10 log(\dfrac{I_1}{I_0})

   I₀ = 10⁻¹² W/m²

now,

30 = 10 log(\dfrac{I_1}{10^{-12}})

\dfrac{I_1}{10^{-12}}= 10^3

I_1= 10^{-8}\ W/m^2

to hear the whisper sound = 80 dB

80 = 10 log(\dfrac{I_2}{10^{-12}})

\dfrac{I_2}{10^{-12}}= 10^8

I_2= 10^{-4}\ W/m^2

we know intensity of sound is inversely proportional to square of distances

\dfrac{I_1}{I_2}=\dfrac{r_2^2}{r_1^2}

\dfrac{10^{-8}}{10^{-4}}=\dfrac{r_2^2}{20^2}

10^{-4}=\dfrac{r_2^2}{20^2}

  r₂ = 0.2 m

6 0
3 years ago
A rescue plane flying horizontally at 72.6 m / s spots a survivor in the ocean 182 m directly below and releases an emergency ki
Mila [183]

Answer:

547 m

Explanation:

From law of motion

s = ut + ½at²

Where "t" is Time taken to reach Earth

s= distance= 182 m

a= vertical acceleration = 5.82 m / s 2

U= initial velocity in vertical position = 0

182= ½ × 5.82t²

t²=( 2× 182)/ 5.82

= 364/5.82

= 62.54

t= √62.54

t= 7.908s

horizontal distance travelled = speed x time

Horizontal speed= 72.6 m / s

horizontal distance travelled =72.6× 7.908

= 547 m

Hence, the survivor will it hit the waves at 547 m away

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2 years ago
List things in your house and put them in order of density
ELEN [110]
I don't know what's in your house! lol. try naming things like: ball, lamp, cup, bowl. 
3 0
3 years ago
Read 2 more answers
Why does a third class lever cannot magnify force?​
maw [93]

Explanation:

The third class lever cannot magnify our force because in third class lever the effort it between the load and the fulcrum. Also, in this type of lever no matter where the force is applied, it is always greater than the force of load. Hence, That type of lever cannot magnify our force.

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3 years ago
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