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AnnZ [28]
2 years ago
7

How long will it take a car to go from 0 to 45 km/hr if they are accelerating at 5 km/hr/s?

Physics
1 answer:
Mandarinka [93]2 years ago
4 0

Answer:

9 seconds

Explanation:

acceleration =  \frac{final \: speed - initial \: speed}{time \: taken}

5km/ hr/ s =  \frac{45 - 0 (km/ h)}{t}

cross multiplying

5t = 45 secs \\ t = 9 \: secs

it will take 9secs for the car to go from 0 to 45 km/ h

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A 1.8 kg uniform rod with a length of 90 cm is attached at one end to a frictionless pivot. It is free to rotate about the pivot
Leokris [45]

Answer:

a. 32.67 rad/s²  b. 29.4 m/s²

Explanation:

a. The initial angular acceleration of the rod

Since torque τ = Iα = WL (since the weight of the rod W is the only force acting on the rod , so it gives it a torque, τ at distance L from the pivot )where I = rotational inertia of uniform rod about pivot = mL²/3 (moment of inertia about an axis through one end of the rod), α = initial angular acceleration, W = weight of rod = mg where m = mass of rod = 1.8 kg and g = acceleration due to gravity = 9.8 m/s² and L = length of rod = 90 cm = 0.9 m.

So, Iα = WL

mL²α/3 = mgL

dividing through by mL, we have

Lα/3 = g

multiplying both sides by 3, we have

Lα = 3g

dividing both sides by L, we have

α = 3g/L

Substituting the values of the variables, we have

α = 3g/L

= 3 × 9.8 m/s²/0.9 m

= 29.4/0.9 rad/s²

= 32.67 rad/s²

b. The initial linear acceleration of the right end of the rod?

The linear acceleration at the initial point is tangential, so a = Lα = 0.9 m × 32.67 rad/s² = 29.4 m/s²

5 0
3 years ago
Two uncharged metal spheres, spaced 25.0 cm apart, have a capacitance of 26.0 pF. How much work would it take to move 12.0 nC of
viktelen [127]

Answer:

W=2.76\times 10^{-6}\ J

Explanation:

Given that,

The distance between two spheres, r = 25 cm = 0.25 m

The capacitance, C = 26 pF = 26×10⁻¹² F

Charge, Q = 12 nC = 12 × 10⁻⁹ C

We need to find the work done in moving the charge. We know that, work done is given by :

U=\dfrac{Q^2}{2C}

Put all the values,

U=\dfrac{(12\times 10^{-9})^2}{2\times 26\times 10^{-12}}\\\\U=2.76\times 10^{-6}\ J

So, the work done is 2.76\times 10^{-6}\ J.

8 0
3 years ago
Which statements describe a fully charged capacitor? Check all that apply.
Oksanka [162]
Well, first of all, there's no such thing as "fully charged" for a capacitor.

A capacitor has a "maximum working voltage", because of mechanical
or chemical reasons, just like a car has a maximum safe speed.  But
anywhere below that, cars and capacitors do their jobs just fine, without
any risk of failing.

So we have a capacitor that has some charge on it, and therefore some
voltage across it.  From the list of choices above . . .

<span>-- Both plates have the same amount of charge.
Yes.  And both plates have opposite TYPES of charge.
One plate is loaded with electrons and is negatively charged.
The other plate is missing electrons and is positively charged.

-- There is a potential difference between the plates.
Yes.  That's the "voltage" mentioned earlier.
It's a measure of how badly the extra electrons want to jump
from the negative plate to the positive plate.

-- Electric potential energy is stored.
Yes.  It's the energy that had to be put into the capacitor
to move electrons away from one plate and cram them
onto the other plate.


</span>
4 0
3 years ago
Read 2 more answers
iron ball weight 400 gram inside water when it is completely impressed in water 53 gram water is displaced what will be the weig
Alika [10]

Answer:

453 gm

Explanation:

<u>Immersed </u>objects are buoyed up by force equal to mass of displaced liquid

400 + 53 = 453 gm  in air

8 0
1 year ago
A piston releases 18 J of heat into its surroundings while expanding from 0.0002 m^3 to 0.0006 m^3 at a constant pressure of 1.0
Elodia [21]

Answer:

value of heat is 18 J

2. step by step

formular w=p(volume1-volume2)

w= 1.0×10^5(0.0006-0.0004)

w= 40 J

8 0
3 years ago
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