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3 years ago

Joe leans against a lamppost with a force of 200 N. The lamppost does not move. How much work does he do?

Physics

1 answer:

hoa [83]3 years ago

6 0

Answer:

No work

Explanation:

He is not moving the lamppost as the lamppost cannot move to begin with.

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A. How long does it take light to travel through a 3.0-mm-thick piece of window glass?

hodyreva [135]

Answer:

a) $1.517\times10^{-11}$ s

b) 3.41 mm

Explanation:

We take the speed of light, c = $3.0\times10^8$ m/s and the refractive index of glass as 1.517.

Speed = distance/time

Time = distance/speed

Refractive index, n = speed of light in vacuum / speed of light in medium

$n=\dfrac{c}{s}$

$s=\dfrac{c}{n}$

$t=\dfrac{d}{c/n}$

$t=\dfrac{dn}{c}$

$t=\dfrac{3\times10^{-3}\times1.517}{3.0\times10^8}$

$t=1.517\times10^{-11}$

We take the refractive index of water as 1.333.

Speed in water = speed in vacuum / refractive index of water

Distance = speed * time

$d=s\times t$

$d=\dfrac{c}{n_w}\times \dfrac{3\times10^{-3}\times1.517}{c}$

$d=\dfrac{3\times10^{-3}\times 1.517}{1.333}$

d = 3.41 mm

6 0

3 years ago

Two magnets are arranged so that they pull together. Which conclusion can be reached? A.Two north poles are together. B. Two sou

Virty [35]

Answer:

Answer is D. a north pole is near a south pole

Explanation:

Hope this helps!! :D

6 0

2 years ago

Read 2 more answers

A close coiled helical spring of round steel wire 10 mm diameter having 10 complete turns with a mean radius of 60 mm is subject

kow [346]

Answer:

The deflection of the spring is 34.56 mm.

Explanation:

Given that,

Diameter = 10 mm

Number of turns = 10

$Radius_{mean} = 60\ mm$

$Diameter_{mean} = 120\ mm$

Load = 200 N

We need to calculate the deflection

Using formula of deflection

$\delta=\dfrac{8pD^3n}{Cd^4}$

Put the value into the formula

$\delta=\dfrac{8\times200\times(120)^3\times10}{80\times10^{3}\times10^4}$

$\delta =34.56\ mm$

Hence, The deflection of the spring is 34.56 mm.

4 0

3 years ago

an object is moving with initial velocity of 5 m/s. After 10 seconds final velocity is 10 m/s. Calculate its acceleration.

Brut [27]

Answer:

0.5m/s2

Explanation:

acceleration= change in velocity/time taken

= v - u/ t

= 10-5/10

=5/10

= 0.5m/s2

6 0

3 years ago

Weigt A box sitting still on the ground by itself has a weight of 700N, what is the mass? (gravity's acceleration is 9.80 m/s2)

Alex

Force=700N
Acceleration=9.8m/s^2

Using newtons law

$\\ \rm\longmapsto F=ma$

$\\ \rm\longmapsto m=\dfrac{F}{a}$

$\\ \rm\longmapsto m=\dfrac{700}{9.8}$

$\\ \rm\longmapsto m=71.4kg$

7 0

2 years ago