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3 years ago

What is the average velocity of a car starting from 0 and travels 7 meters in 9 seconds?

Physics

1 answer:

Leni [432]3 years ago

5 0

Your question has been heard loud and clear.

Averge velocity formula= Total distance travelled / total time taken.

Total distance=7meters

Total time taken=9 seconds.

Average velocity = 7/9= 0.77 metres/second

Average velocity= 0.77m/s

Thank you.

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An object at 27°C has its temperature increased to 37°C.

Firlakuza [10]

Answer:

b. 14

Explanation:

$T_{i}$ = Initial temperature = 27 °C = 27 + 273 = 300 K

$T_{f}$ = Final temperature = 37 °C = 37 + 273 = 310 K

$P_{i}$ = Initial Power radiated by the object

$P_{f}$ = Final Power radiated by the object

We know that the power radiated is directly proportional to fourth power of the temperature. hence

$\frac{P_{f}}{P_{i}} = \frac{T_{f}^{4} }{T_{i}^{4} }\\\frac{P_{f}}{P_{i}} = \frac{(310)^{4} }{(300)^{4} }\\\frac{P_{f}}{P_{i}} = 1.14\\P_{f} = (1.14) P_{i}$

Percentage increase in power is given as

$\frac{(P_{f} - P_{i})\times100}{P_{i}} \\\frac{((1.14) P_{i} - P_{i})\times100}{P_{i}} \\14$

3 0

3 years ago

Tensile stress is: A. the strain per unit length. B. the ratio of elastic modulus to strain. C. the ratio of the change in lengt

victus00 [196]

Answer:

D. the same as force. the applied force per cross-sectional area.

Explanation:

Tensile stress of a material is defined as the ratio of the applied force on the material to its cross sectional area. this is expressed mathematically as;

Tensile stress = Force/cross sectional area

Tensile stress = F/A

Force is measured in newton while cross sectional area is measured in m

Hence the unit of Tensile stress is N/m²

6 0

3 years ago

A projectile enters a resisting medium at x = 0 with an initial velocity v0 = 910 ft/s and travels 5 in. before coming to rest.

evablogger [386]

Answer:

a = - 1.987 × 10⁶ ft/s²

t = 6.84 × 10⁻⁴ s

Explanation:

v₀ = 910 ft/s

x = 5 in.

relation v = v₀ - k x

v = 0 as body comes to rest

0 = 900 - 5k/12

k = 2184 s⁻¹

acceleration

$\frac{\mathrm{d} v}{\mathrm{d} t} = -k\frac{\mathrm{d} x}{\mathrm{d} t}$

where

(A) a = -k × v

at v= 910 ft/s

a = - 1.987 × 10⁶ ft/s²

(B) at x = 3.9 in.

v = 910 - 3.9(2184)/12

v = 200.2 m/s

$\frac{\mathrm{d} v}{\mathrm{d} t} = -k\frac{\mathrm{d} x}{\mathrm{d} t}$

$\frac{dv}{v} = -kdt$

$\int\limits^{200.2}_{900} {\frac{1}{v} }dv = -k\int\limits^t_0 dt$

$ln(200.2)-ln(900) = -kt$

t = 6.84 × 10⁻⁴ s

3 0

2 years ago

A dog, that has a mass of 16 kgs, runs across a yard. What is the average force applied to the dog from the ground as it runs ac

VikaD [51]

Answer:

156.96 N

Explanation:

F=ma where m is the mass and a is acceleration

Substituting 16 Kg for m and 9.81 m/s2 for g then

F=16*9.81= 156.96 N

4 0

3 years ago

(a) the gamma rays produced by a radioactive nuclide used in medical imaging (b) radiation from an FM radio station at 93.1 MHz

lawyer [7]

Answer:

They can be rank in the following way:

A radio signal from an AM radio station at 680 kHz on the dial

Radiation from an FM radio station at 93.1 MHz on the dial

The red light of a light-emitting diode, such as in a calculator

The yellow light from sodium vapor streetlights

The gamma rays produced by a radioactive nuclide used in medical

Explanation:

The electromagnetic spectrum is the distribution of radiation due to the different frequencies at which it radiates and its different intensities, that radiation is formed by electromagnetic waves, which are transverse waves formed by an electric field and a magnetic field perpendicular to it.

Radiation is distributed along that electromagnetic spectrum according to the wavelength or frequency.

Highest frequencies

X-rays

Ultraviolet rays

Visible region

Lower frequencies

Infrared

Microwave

Radio waves

Radio waves and the visible region (yellow light, red light) are part of the electromagnetic spectrum, any radiation of that electromagnetic spectrum has a speed of 3.00x10^{8}m/s in vacuum.

However, the following equation relates the velocity, the frequency, and the wavelength:

$c = \nu \cdot \lambda$ (1)