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3 years ago

At what speed will a box be falling at a time t = 0.75 s after being dropped?

Physics

1 answer:

IRINA_888 [86]3 years ago

8 0

Explanation:

Initial speed(u)= 0 m/s (Ball is dropped)

time(t)= 0.75 s

acceleration(a)= 10 m/s² (gravity)

Final speed(v)= u+at

v=0+(10)× 0.75

v=7.5 m/s

Speed is 7.5 m/s

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Power is the product of_____.

tia_tia [17]

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All options are wrong here.

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Work/Time.

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3 years ago

Halleys comet has period of 75.3 years. Using Kepler’s third law, find it’s semimajor axis expressed in astronomical units?

natta225 [31]

Answer: 17.83 AU

Explanation:

According to Kepler’s Third Law of Planetary motion “The square of the orbital period of a planet is proportional to the cube of the semi-major axis (size) of its orbit”. 

$T^{2}\propto a^{3}$ (1)

Talking in general, this law states a relation between the orbital period $T$ of a body (moon, planet, satellite, comet) orbiting a greater body in space with the size $a$ of its orbit.

However, if $T$ is measured in years, and $a$ is measured in astronomical units (equivalent to the distance between the Sun and the Earth: $1AU=1.5(10)^{8}km$ ), equation (1) becomes:

$T^{2}=a^{3}$ (2)

This means that now both sides of the equation are equal.

Knowing $T=75.3years$ and isolating $a$ from (2):

$a=\sqrt[3]{T^{2}}=T^{2/3}$ (3)

$a=(75.3years)^{2/3}$ (4)

Finally:

$a=17.83AU$ (5)

4 0

3 years ago

In a milkans apparatus,an oil drop of weight 2.0×10^-15kg accquires two surplus electrons. when a Potential difference of 620 vo

andriy [413]

Answer:

r = 9.92 mm

Explanation:

Given that,

Mass of oil drop, $m=2\times 10^{-15}\ kg$

It acquires 2 surplus electrons, q = +2e $=3.2\times 10^{-19}\ C$

Potential difference, V = 620 V

Thie potential difference is applied between the pair of horizontal metal plates the drop is in equilibrium.

We need to find the distance between the plates.

At equilibrium,

mg = qE

Since, E = V/r (r is distance between plates)

$mg=\dfrac{qV}{r}\\\\r=\dfrac{qV}{mg}\\\\r=\dfrac{3.2\times 10^{-19}\times 620}{2\times 10^{-15}\times 10}\\\\=0.00992\ m\\\\=9.92\ mm$

So, the distance between the plates is 9.92 mm.

6 0

3 years ago

If it takes 42 minutes to load 3 1/2 trucks, how many minutes will it take to load 6 1/2 trucks?

Kruka [31]

If it takes 42 minutes to load 3 1/2 trucks, then it takes 42 / 3.5 = 12 minutes to load a single truck. Multiplying the number of minutes per truck by 6.5 yields the time it will take to load. In this case 12 x 6.5 = 78 minutes would be required to load 6 1/2 trucks. The formula for the time taken is t = 12n, where t is the time in minutes and n is the number of trucks.

6 0

3 years ago

A 800N student does a handstand with both hands at an angle of 15 degrees from the vertical what is the force on each hand

jeyben [28]

here we can say that net force on the student vertically upwards will be counter balance by his weight downwards

Let net force F is exerted by each hand

so here we will have

$2Fcos15 = W$