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Sveta_85 [38]
3 years ago
7

Show your working please ​

Physics
1 answer:
saw5 [17]3 years ago
3 0

Explanation:

There's not enough information in the problem to solve it.  We need to know either the initial speed of the lorry, or the time it takes to stop.

For example, if we assume the initial speed of the lorry is 25 m/s, then we can find the rate of deceleration:

v² = v₀² + 2aΔx

(0 m/s)² = (25 m/s)² + 2a (50 m)

a = -6.25 m/s²

We can then use Newton's second law to find the force:

F = ma

F = (7520 kg) (-6.25 m/s²)

F = -47000 N

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Seven seconds after a brilliant flash of lightning, thunder shakes the house. How far was the lightning strike from the house? S
Zepler [3.9K]

Answer:

About two kilometers away

\rm distance=2.401\ km

Explanation:

Given:

The time gap between the light and sound to travel to the house, t=7\ s

<em>Since the clouds are formed in the troposphere region of the atmosphere which extends from 8 kilometers to 12 kilometers above the earth-surface and the velocity of light is 300000 kilometers per second so it is visible almost instantly, hence we neglect the time taken by the light to travel to the house from the clouds.</em>

<u>∴Distance between the lightning-strike and the house:</u>

\rm distance=v\times t

we have the speed of sound as: v=343\ m.s^{-1}

So,

\rm distance=343\times 7

\rm distance=2401\ m

\rm distance=2.401\ km

6 0
2 years ago
The y-component of a projectile’s velocity is 12.1 m/s. When the projectile once again passes by the height from which it was la
Nat2105 [25]
It's 12.1 m/s, assuming that's the launch velocity that's given.
For projectile motion, velocity's y-component is parabolic/quadratic. It's x-component is constant, so you don't need to know it. 
6 0
2 years ago
A powerful motorcycle can produce an acceleration of 3.00 m/s2 while traveling at 90.0 km/h. At that speed the forces resisting
nata0808 [166]

Answer:

1185 N

Explanation:

From Newton’s second law of motion,  

F=ma where m= mass of motorcycle, a is acceleration of the motorcycle and F=Force

Net force acting on motorcycle F_{net} is given by  F_{net}=F-f

Where F is force acting on motorcycle and f is frictional force

Substituting F-f for F_{net}

F_{net}=ma hence  ma= F- f Substituting a with 3, m with 245Kg and f with 450N as provided

245*3= F- 450

F=245*3 +450= 1185 N

6 0
3 years ago
A record player turntable initially rotating at 3313 rev/min is braked to a stop at a constant rotational acceleration. The turn
Rus_ich [418]

Answer:

(A) It will take 22 sec to come in rest

(b) Work done for coming in rest will be 0.2131 J              

Explanation:

We have given the player turntable initially rotating at speed of 33\frac{1}{3}rpm=33.333rpm=\frac{2\times 3.14\times 33.333}{60}=3.49rad/sec

Now speed is reduced by 75 %

So final speed \frac{3.49\times 75}{100}=2.6175rad/sec

Time t = 5.5 sec

From first equation of motion we know that '

\alpha =\frac{\omega -\omega _0}{t}=\frac{2.6175-3.49}{4}=-0.158rad/sec^2

(a) Now final velocity \omega =0rad/sec

So time t to come in rest  t=\frac{0-3.49}{-0.158}=22sec

(b) The work done in coming rest is given by

\frac{1}{2}I\left ( \omega ^2-\omega _0^2 \right )=\frac{1}{2}\times 0.035\times (0^2-3.49^2)=0.2131J

4 0
2 years ago
Identify the pros and cons of using mirrors versus lenses in each of the following applications:
disa [49]

Answer:

Explanation:

A lens – An object, usually made of glass, that focuses or defocuses the light that passes through it.

A mirror – A smooth surface, usually made of glass with reflective material painted on the underside, that reflects light so as to give an image of what is in front of it.

Telescope – monocular optical instrument possessing magnification for observing distant objects, especially in astronomy.

Refracting telescopes – are telescopes that use lenses are and those that use concave parabolic mirrors are called reflecting telescopes. 

Pros of mirror telescope

• They are easier to construct and not expensive to produce

• made larger and more durable (more light can be directed to the eyepiece which is good)

• cannot have any occlusions 

• mirrors have less spherical aberration

• reflect all wavelengths of light equally

• more magnification power for cheaper version

Cons of mirror prisms

• it must also be realigned after cleaning, which can be expensive - maintenance disadvantage

• Reflective Surface Disadvantage

Pros of Lenses telescope

• Easy to use

• More reliable

Cons of Lens telescope

• are not easy to construct and expensive to produce

• May have occlusions

• spherical aberration are more

• Doesnt reflect wavelengths of light equally they bend light differently

• Less magnification power for cheaper version

• heavy

• Longer body

Pro of Mirror periscope

• it helps us to see further than our view that is what is above us or sometimes even below us.

•Light weight

disadvantage:

• it may not work properly and show distorted images due to fog. ; Some have a narrow field of view ; May be detected by others Ungainly (long, takes up space),

•Not as rugged as prisms.

• Maintenance of reflection surface

Pros of Prism periscopes

• incorporated lenses for magnification and function as telescopes.

• They typically employ prisms and total internal reflection instead of mirrors, because prisms, which do not require coatings on the reflecting surface, are much more rugged than mirrors.

• May be fitted with additional optical capabilities such as range-finding and targeting.

Cons.

•mechanically disadvantage: Complex optically ; Some have a narrow field of view ; May be detected by others 

Ungainly (long, takes up space)

• Heavy weight

Lens - Terrestrial telescope

Pro: An advantage is that it makes it possible to vary the magnification of the telescope.

Cons- This system has the disadvantage increasing the length of the telescope.

Mirror- Terrestrial telescope (Cassegrain)

Pro: Good for distant terrestrial viewing.

greater magnification is attained.

They are more shorter

Cons- It is not what people expect a telescope to look like.

Slight light loss due to secondary mirror obstruction compared to refractors. Generally not suited for most terrestrial applications nor for to view objects in the sky.

6 0
2 years ago
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