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3 years ago

A world-class tennis player can serve a tennis ball at 150 mi/h (about 67 m/s). The length of a tennis

Physics

1 answer:

Rudik [331]3 years ago

5 0

Answer:

The expression for the time taken by an object to move with a speed at some distance is,

t= d/v

Here, t is the time taken by the opponent to react, d is the length of the court, andis the speed of the ball.

Explanation:

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_________ is stored energy.

Ivan

Answer:

I think so is b kinetic o a potential

5 0

3 years ago

A 13.0 g piece of Styrofoam carries a net charge of â5.40 Î¼C and floats above the center of a large horizontal sheet of plastic

kati45 [8]

Answer:

σ =4.180×10^{-9} C/m^2

Explanation:

electric field due to non conducting sheet is

$E=\frac{\sigma}{2\epsilon_0}$

the force acting on the piece of Styrofoam

Eq= mg

⇒E= mg/q

now,

$\frac{mg}{q} = \frac{\sigma}{2\epsilon_0}$

⇒ $\sigma= \frac{2mg\epsilon_0}{q}$

$\sigma= \frac{2\times0.013\times9.81\times8.85\times10^{-12}}{5.40\times10^{-4}}$

charge per unit area (in C/m2) on the plastic sheet σ =4.180×10^{-9} C/m^2

6 0

3 years ago

What unit do we use for pressure

-Dominant- [34]

Answer:

Pascal

Explanation:

5 0

3 years ago

Read 2 more answers

The energy of the electron in Hydrogen atom can be shown to be given by En = -13.6/n^2 eV, where n represents the principal quan

Tpy6a [65]

Answer:

This represents radiation in ultra-violet region .

Explanation:

Energy of the orbit where n = 3 is given as follows

$E_3 =- \frac{13.6 }{3^2}$

$E_3 =- \frac{13.6 }{9}$ = -1.511 eV

Energy of the orbit where n = 1 is given as follows

$E_1 =- \frac{13.6 }{1^2}$

$E_1 =- \frac{13.6 }{1}$ = 13.6 eV

Difference of [tex]E_3 and [tex]E_1 = - 1.511+ 13.6

= 12.089 eV.

The wavelength of light having this energy in nm is given by the expression as follows

Wavelength in nm = 1244 / energy in eV

= 1244 / 12.089

= 102.90 nm

This represents radiation in ultra-violet region .

8 0

3 years ago

A butcher has a beam balance and masses 0.5kg and 2kg.How would he measure 1.5kg of meat on the balance at once

LekaFEV [45]

Answer and Explanation:

The butcher will balance the meat and the 0.5 kg mass on one side of the beam balance and 2 kg mass on the other side of the beam balance.
By so doing, when the beam balances then the amount of meat measured will be exactly 1.5 kg as required. Since the 1.5 kg meat and 0.5 kg mass is equivalent to the 2 kg on the other side of the beam balance.

6 0

3 years ago