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3 years ago

PLEASE HELP

Physics

2 answers:

Gala2k [10]3 years ago

6 0

Answer:

Explanation:

Just did on APEX

Ilia_Sergeevich [38]3 years ago

5 0

Answer:

Explanation:

I believe its A because lets say the ice is alone in a jar with nothing inside no water no other ice just be its self. You put that jar inside the freezer, for 18 hours. It's not going to be heaver nor lighter so the obvious answer would be A. because you gained nothing from that ice cube it will just have to stay the same. Sorry if I'm wrong

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Question 4. Calculate the kinetic energy of a Year 11 pupil (mass 55Kg)

bogdanovich [222]

Answer:

990 J

Explanation:

Kinetic energy is:

KE = ½ mv²

Given m = 55 kg and v = 6 m/s:

KE = ½ (55 kg) (6 m/s)²

KE = 990 J

4 0

3 years ago

What is the maximum kinetic energy of ejected electrons when photons of wavelength 300 nm hit a metal that has a work function o

Sonja [21]

Explanation:

Given that,

Wavelength of the photon, $\lambda=300\ nm=3\times 10^{-7}\ m$

Work function of the metal, $\phi=1.13\ eV=1.81\times 10^{-19}\ J$

We need to find the maximum kinetic energy of the ejected electrons. It can be calculated using Einstein's photoelectric equation as :

$hf=E_k+\phi$

$E_k=hf-\phi$

$E_k=h\dfrac{c}{\lambda}-\phi$

$E_k=6.63\times 10^{-34}\times \dfrac{3\times 10^8}{3\times 10^{-7}}-1.81\times 10^{-19}$

$E_k=4.82\times 10^{-19}\ J$

$E_k=3.01\ eV$

$E_k=3\ eV$

So, the maximum kinetic energy of the ejected electrons is 3 ev. Hence, this is the required solution.

3 0

3 years ago

You should ALWAYS carry the microscope by placing your hand on the base of the microscope and gripping the red handle with your

marin [14]

Answer:

true

Explanation:

place hand under base and one on the arm/handle

4 0

3 years ago

How is reflection of light evident in nature ?

Stolb23 [73]

Answer:

Reflection is when light bounces of an object. If the surface is smooth and shiny, like glass, water or polished metal, the light will reflect at the same angle as it hit the surface.

5 0

3 years ago

a rugby player passes the ball 5.34 m across the field, where it is caught at the same height as it left his hand. at what angle

MakcuM [25]

Answer:

$31.035^{\circ}$

Explanation:

x = Displacement in x direction = 5.34 m

t = Time taken to travel the displacement

y = Displacement in y direction = 0

u = Initial velocity of ball = 7.7 m/s

g = Acceleration due to gravity = $9.81\ \text{m/s}^2$

Displacement in x direction is given by

$x=u\cos\theta t\\\Rightarrow t=\dfrac{5.34}{7.7 \cos\theta}$

Displacement in y direction is given by

$y=u\sin\theta t-\dfrac{1}{2}gt^2\\\Rightarrow 0=7.7\sin\theta \dfrac{5.34}{7.7\cos\theta}-\dfrac{1}{2}\times 9.81 (\dfrac{5.34}{7.7\cos\theta})^2\\\Rightarrow 0=7.7\sin\theta-4.905\times \dfrac{5.34}{7.7\cos\theta}\\\Rightarrow 0=7.7^2\sin\theta \cos\theta-4.905\times 5.34\\\Rightarrow 0=7.7^2\dfrac{\sin2\theta}{2}-4.905\times 5.34\\\Rightarrow 0=7.7^2\sin2\theta-4.905\times5.34\times 2\\\Rightarrow \sin2\theta=\dfrac{4.905\times 5.34\times 2}{7.7^2}\\\Rightarrow 2\theta=\sin^{-1}\dfrac{4.905\times 5.34\times 2}{7.7^2}$

$\Rightarrow \theta=\dfrac{62.07}{2}\\\Rightarrow \theta=31.035^{\circ}$

The angle at which the ball was thrown is $31.035^{\circ}$ .

7 0

3 years ago