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olya-2409 [2.1K]
3 years ago
9

The best rebounders in basketball have a vertical leap (that is, the vertical movement of a fixed point on their body) of about

100 cm . a) What is their initial "launch" speed off the ground?
b)How long are they in the air?
Physics
1 answer:
nadya68 [22]3 years ago
6 0

Answer:

a) 4.45 m/s

b) 0.9 seconds

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration due to gravity = 9.81 m/s²

v^2-u^2=2as\\\Rightarrow -u^2=2as-v^2\\\Rightarrow u=\sqrt{v^2-2as}\\\Rightarrow u=\sqrt{0^2-2\times -9.81\times 1}\\\Rightarrow u=4.45\ m/s

a) The vertical speed when the player leaves the ground is 4.45 m/s

v=u+at\\\Rightarrow t=\frac{v-u}{a}\\\Rightarrow t=\frac{0-4.45}{-9.81}\\\Rightarrow t=0.45\ s

Time taken to reach the maximum height is 0.45 seconds

s=ut+\frac{1}{2}at^2\\\Rightarrow 1=0t+\frac{1}{2}\times 9.81\times t^2\\\Rightarrow t=\sqrt{\frac{1\times 2}{9.81}}\\\Rightarrow t=0.45\ s

Time taken to reach the ground from the maximum height is 0.45 seconds

b) Time the player stayed in the air is 0.45+0.45 = 0.9 seconds

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GenaCL600 [577]

Answer:

(a)106.4C

b)0.5676mm

Explanation:

(a)To get the charge that have passed through the starter then The current will be multiplied by the duration

I= current

t= time taken

Q= required charge

Q= I*t = 140*0.760 = 106.C

(b) b. How far does an electron travel along the wire while the starter motor is on?(mm)

diameter of the conductor is 4.20 mm

But Radius= diameter/2= 4.20/2=

The radius of the conductor is 2.1mm, then if we convert to metre for consistency same then

radius of the conductor is 0.0021m.

We can now calculate the area of the conductor which is

A = π*r^2

= π*(0.0021)^2 = 13.85*10^-6 m^2

We can proceed to calculate the current density below

J = 140/13.85*10^-6 = 10108303A/m

According to the listed reference:

Where e= 1.6*10^-19

n= 8.46*10^28

Vd = J/(n*e) = 10108303/ ( 8.46*10^28 * 1.6*10^-19 ) =0.0007468m/s=0 .7468 mm/s

Therefore , the distance traveled is:

x = v*t = 0.7468 * 0.760 = 0.5676mm

7 0
3 years ago
A 10.0kg water balloon is dropped from a height of 12.0m. Calculate the speed of the balloon just before it hits the ground
kolbaska11 [484]

Answer:

15.5 m/s.

Explanation:

Potential energy of the balloon has been converted to kinetic energy.

potential energy = kinetic energy.

mgh = ½mv².

10* 10* 12= ½ *10 *v²

1200 = 5v²

v²=1200÷5

v=√240

v= 15.49~15.5 m/s.

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Sugar molecules can be oxidized in the cell of animals . This oxidation releases energy for the animal to use. From what soured
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3 years ago
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A ship sails west for 100km and then south for 100km. What is the displacement?
ale4655 [162]

\sf \vec{w}=100

  • \sf \vec{s}=100

For displacement apply Pythagorean theorem

\\ \rm\hookrightarrow 100^2+100^2

\\ \rm\hookrightarrow 10000+10000

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4 0
2 years ago
1. Compare the speed that light waves travel in air to the speed that sound waves travel in the air. How many times faster do li
Vladimir79 [104]

Answer:

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Explanation:

From the question given above, the following data were obtained:

Speed of sound in air (v) = 335 m/s

Speed of light in air (c) = 3×10⁸ m/s

How many times faster =.?

To obtain how many times faster light travels in air than sound, do the following

c : v => 3×10⁸ : 335

c/v = 3×10⁸ / 335

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Cross multiply

c = 895522 × v

From the illustrations made above, we can see that the speed of the light in air (c) is 895522 times the speed of sound in air.

Thus, light travels 895522 times faster than sound in air.

6 0
2 years ago
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