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FrozenT [24]
3 years ago
5

Help please suffering

Physics
1 answer:
inessss [21]3 years ago
3 0

Assuming Lin jumps from and returns to the same level ground, the fact that he stays in the air for 0.8 seconds means it takes him 0.4 seconds to reach his maximum height, at which point his vertical velocity will be 0.

Acceleration is a constant g in the downward direction, and when it's constant it's the same as the average acceleration over any given time interval. Over the 0.4 second interval during which he reaches his maximum height, we have

a_{\rm avg}=-g=\dfrac{0-v_0}{0.4\,\rm s}\implies v_0=3.9\,\dfrac{\rm m}{\rm s}

which is also the same speed he will have when he returns to the ground.

To find the maximum height, we have

0^2-{v_0}^2=2(-g)y_{\rm max}\implies y_{\rm max}=0.78\,\rm m

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lilavasa [31]

Answer:

7 meters per second or 7 m/s

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A spring has a spring constant of 20 N/m. How much potential energy is stored in the spring as it stretched 0.20 m
makkiz [27]
The elastic potential energy (Ep) is given by Ep = \frac{1}{2}*k*x^2

Data: 
Ep = ? (Joule)
k = 20 N/m
x (displacement) = 0.20 m

Solving:
Ep = \frac{1}{2}*k*x^2
Ep = \frac{1}{2}*20*0.20^2
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\boxed{\boxed{Ep = 0.4\:J}}\end{array}}\qquad\quad\checkmark
7 0
3 years ago
Written:
zmey [24]

Answer:

0.833

Explanation:

Power = energy / time

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P = 8.33 kW

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e = 8.33 kW / 10.0 kW

e = 0.833

5 0
3 years ago
If a Stone with an of original velocity of zero is falling from a ledge and takes eight seconds to hit the ground what is the fi
DaniilM [7]
Let t=time to reach the ground=8 secs, g= acceleration of gravity. The speed v on reaching the ground is gt=8g=78.4 m/s where g=9.8 m/s/s approx.
3 0
3 years ago
Two identical resistors connected in series have an equivalent resistance of 4 ohms. The same two resistors, when connected in p
irina1246 [14]

Answer:

1 ohm

Explanation:

since there are two identical resistors, one resistor will be

R = \frac{4}{2} =2ohm [ proven as in series R_{e} = 2 + 2 = 4ohm ]

to calculate the equivalent resistance when in parallel:

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so,

\frac{1}{R_{e} } = \frac{1}{2} + \frac{1}{2}

R_{e} = 1ohm

4 0
2 years ago
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