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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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Explain the difference between speed and vilocity?

Zolol [24]

Answer:

The short answer is that velocity is the speed with a direction, while speed does not have a direction.

Explanation:

Speed is how fast an object is moving. It is calculated by the displacement of space per a unit of time. Velocity is the rate at which an object changes position in a certain direction. It is calculated by the displacement of space per a unit of time in a certain direction. Velocity deals with direction, while speed does not.

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3 years ago

When the magnetic flux through a single loop of wire increases by , an average current of 40 A is induced in the wire. Assuming

Zielflug [23.3K]

COMPLETE QUESTION:

When the magnetic flux through a single loop of wire increases by 30 Tm^2 , an average current of 40 A is induced in the wire. Assuming that the wire has a resistance of 2.5 ohms , (a) over what period of time did the flux increase? (b) If the current had been only 20 A, how long would the flux increase have taken?

Answer:

(a). The time period is 0.3s.

(b). The time period is 0.6s.

Explanation:

Faraday's law says that for one loop of wire the emf $\varepsilon$ is

$(1). \: \: \varepsilon = \dfrac{\Delta \Phi_B}{\Delta t }$

and since from Ohm's law

$\varepsilon = IR$ ,

then equation (1) becomes

$(2). \: \:IR= \dfrac{\Delta \Phi_B}{\Delta t }.$

(a).

We are told that the change in magnetic flux is $\Phi_B = 30Tm^2$ , the current induced is $I = 40A$ , and the resistance of the wire is $R = 2.5\Omega$ ; therefore, equation (2) gives

$(40A)(2.5\Omega)= \dfrac{30Tm^2}{\Delta t },$

which we solve for $\Delta t$ to get:

$\Delta t = \dfrac{30Tm^2}{(40A)(2.5\Omega)},$

$\boxed{\Delta t = 0.3s}$ ,

which is the period of time over which the magnetic flux increased.

(b).

Now, if the current had been $I =20A$ , then equation (2) would give

$(20A)(2.5\Omega)= \dfrac{30Tm^2}{\Delta t },$

$\Delta t = \dfrac{30Tm^2}{(20A)(2.5\Omega)},$

$\boxed{\Delta t = 0.6 s\\}$

which is a longer time interval than what we got in part a, which is understandable because in part a the rate of change of flux $\dfrac{\Delta \Phi_B}{\Delta t}$ is greater than in part b, and therefore , the current in (a) is greater than in (b).

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3 years ago

A meter rule balance on a knife headge at the 55cm mark wheb a mass of 40g from 995cm .find the mass of the meter rule.

umka2103 [35]

Answer:

Let the weight of the ruler be X.

Now X acts in the middle, so we have 55-50 = 50cm

Since left hand movement= right hand movement

X(55-50)=90(95-55)

5X= 90×40

X=320cm

Hence the weight of the ruler is 320g

Explanation:

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3 years ago

Compare an earthquake with a Richter scale magnitude of 5.5 to one with a magnitude of 7.5.

maksim [4K]

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3 years ago

006 (part 1 of 2) 10.0 points

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Snow balls can be fun. In the winter time, and in the Turkey season

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3 years ago