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3 years ago

What is the difference between density and specific gravity

1 answer:

4 0

Density is defined as mass per unit volume. It has the SI unit kg m-3 or Kg/m-3 and is an absolute quantity. Specific gravity is the ratio of a material's density with that of water at 4 °C (where it is most dense and is taken to have the value 999.974 kg·m-3). It is therefore a relative quantity with no units.

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Enter the expression 2cos2(θ)−1, where θ is the lowercase Greek letter theta.

stiv31 [10]

2cos2(θ)−1 = 0
2cos2(θ)=1
cos2(θ)=1/2
2θ=arc cos1/2
2θ=60 degrees
θ=30 degrees

4 0

3 years ago

Pls someone help with number 3

mars1129 [50]

Rocket thrust equation
= ( mass flow rate of fuel burnt ) X (Velocity of gas ejected ) + ( Exit Pressure - Outdoor Pressure ) X ( Area of exhaust )

In this case, we can assume the exit pressure = outdoor pressure and since area of exhaust is not given, it can be assumed to be negligible.

In this case, by Newton 3rd’s law,

Force exerted by gas on rocket
= Force exerted by rocket on gas
= (10kg/s) X (5 x 10^3 m/s)
= 5 x 10^4 N

7 0

3 years ago

A uniform disk with radius 0.650 m

VashaNatasha [74]

Answer:

$a = 13.758\,\frac{m}{s^{2}}$

Explanation:

First, the instant associated to the angular displacement is:

$(1.10\,\frac{rad}{s} )\cdot t + (6.30\,\frac{rad}{s^{3}} )\cdot t^{2} - 0.628\,rad = 0$

Roots of the second-order polynomial are:

$t_{1} \approx 0.240\,s, t_{2} \approx -0.415\,s$

Only the first root is physically reasonable.

The angular velocity is obtained by deriving the angular displacement function:

$\omega (0.240\,s) = 1.10\,\frac{rad}{s}+ (12.6\,\frac{rad}{s^{2}})\cdot (0.240\,s)$

$\omega (0.240\,s) = 4.124\,\frac{rad}{s}$

The angular acceleration is obtained by deriving the previous function:

$\alpha (0.240\,s) = 12.6\,\frac{rad}{s^{2}}$

The resultant linear acceleration on the rim of the disk is:

$a_{t} = (0.650\,m)\cdot (12.6\,\frac{rad}{s^{2}} )$

$a_{t} = 8.190\,\frac{m}{s^{2}}$

$a_{n} = (0.650\,m)\cdot (4.124\,\frac{rad}{s} )^{2}$

$a_{n} = 11.055\,\frac{m}{s^{2}}$

$a = \sqrt{a_{t}^{2}+a_{n}^{2}}$

$a = 13.758\,\frac{m}{s^{2}}$

3 0

3 years ago

A vehicle in for repair has a burst upper radiator tank. Technician A says thermostat that was stuck in the open position could

Morgarella [4.7K]

Answer:

Technician B

Explanation:

A thermostat being stuck in an open position allows coolant to constantly circulate through the radiator which will cause a drop in the temperature of the engine. Hence, thermostat being stuck in an open position has nothing to do with burst upper radiator.

On the other hand, a radiator cap controls the pressure within the radiator which needs to be kept constant in order prevent overheating or damage to the radiator itself.

Therefore, technician B is correct.

5 0

3 years ago

When drawing a free body diagram, which of the following things would NOT be included

Neko [114]

C. Mass of the object

5 0

3 years ago