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3 years ago

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Which of the following quantity is unit-less? 1 Specific gravity 2 Mass density 3 Acceleration due to gravity 4 All of the above

1 answer:

julia-pushkina [17]3 years ago

4 0

Answer:

1

Explanation:

Specific gravity is a ratio (of 2 densities) so it has no unit.

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A car leaves an intersection traveling west. Its position 4 sec later is 21 ft from the intersection. At the same time, another

Alex_Xolod [135]

Answer:

15.8 ft/s

Explanation:

$\frac{da}{dt}$ = Velocity of car A = 9 ft/s

a = Distance car A travels = 21 ft

$\frac{db}{dt}$ = Velocity of car B = 13 ft/s

b = Distance car B travels = ft

c = Distance between A and B after 4 seconds = √(a²+b²) = √(21²+28²) = √1225 ft

From Pythagoras theorem

a²+b² = c²

Now, differentiating with respect to time

$2a\frac{da}{dt}+2b\frac{db}{dt}=2c\frac{dc}{dt}\\\Rightarrow a\frac{da}{dt}+b\frac{db}{dt}=c\frac{dc}{dt}\\\Rightarrow \frac{dc}{dt}=\frac{a\frac{da}{dt}+b\frac{db}{dt}}{c}\\\Rightarrow \frac{dc}{dt}=\frac{21\times 9+28\times 13}{\sqrt{1225}}\\\Rightarrow \frac{dc}{dt}=15.8\ ft/s$

∴ Rate at which distance between the cars is increasing three hours later is 15.8 ft/s

6 0

4 years ago

When a negatively charged object moves in the opposite direction of an electric force field, the potential energy of the object

Simora [160]

The best and most correct answer among the choices provided by the question is decreases <span>.

</span>The potential energy of the object <span>decreases.</span>

Hope my answer would be a great help for you.
If you have more questions feel free to ask here at Brainly.

3 0

3 years ago

Read 2 more answers

Consider a bicycle wheel to be a ring of radius 30 cm and mass 1.5 kg. Neglect the mass of the axle and sprocket. If a force of

Charra [1.4K]

To solve the problem it is necessary to apply the Torque equations and their respective definitions.

The Torque is defined as,

$\tau = I \alpha$

Where,

I=Inertial Moment

$\alpha =$ Angular acceleration

Also Torque with linear equation is defined as,

$\tau = F*d$

Where,

F = Force

d= distance

Our dates are given as,

R = 30 cm = 0.3m

m = 1.5 kg

F = 20 N

r = 4.0 cm = 0.04 m

t = 4.0s

Therefore matching two equation we have that,

$d*F = I\alpha$

For a wheel the moment inertia is defined as,

I= mR2, replacing we have

$d*F= \frac{mR^2a}{R}$

$d*F= mRa$

$a = \frac{rF}{ mR}$

$a = \frac{0.04*20}{1.5*0.3}$

$a=1.77 m/s^2$

Then the velocity of the wheel is

$V = a *t \\V=1.77*4 \\V=7.11 m/s$

Therefore the correct answer is D.

4 0

3 years ago

Raising 100 grams of water from 40 to 60 °C (the specific heat capacity of water is 1

faust18 [17]

Heat in a system can be calculated by multiplying the given mass to the specific heat capacity of the substance and the temperature difference. It is expressed as follows:<span>

Heat = mC(T2-T1)
Heat = 100(1)(60-20)
<span>Heat = 4000 calories addition to the system</span></span>

<span><span>
</span></span>

<span><span>Hope this answers the question. Have a nice day.</span></span>

4 0

3 years ago

A coil 3.85 cm radius, containing 450 turns, is placed in a uniform magnetic field that varies with time according to B=( 1.20×1

Nimfa-mama [501]

Answer:

0.025V + (0.000218V/s³) t³

Explanation:

Parameters given:

Radius of coil, r = 3.85 cm = 0.0385 m

Number of turns, N = 450

Magnetic field, B = ( 1.20×10^(−2) T/s )t + (2.60×10^(−5) T/s4 )t^4.

The magnitude of Induced EMF is given as:

E = N * A * dB/dt

Where A is the area of the coil

First, we differentiate the magnetic field with respect to time:

dB/dt = 0.012 + 0.000104t³

Therefore, EMF will be:

E = 450 * 3.142 * (0.012 + 0.000104t³)

E = 2.096(0.012 + 0.000104t³)

E = 0.025V + (0.000218V/s³)t³

6 0

3 years ago

Read 2 more answers