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2 years ago

12

A car of mass 1200Kilograms moving at 15 m/s the driver applies the brakes for 0.08 seconds and the castles down to 10 meter per

second calculate the acceleration of the car

1 answer:

denpristay [2]2 years ago

5 0

Initial velocity=u=15m/s
Final velocity=v=10m/s
Time=0.08s

$\\ \sf\longmapsto Acceleration=\dfrac{v-u}{t}$

$\\ \sf\longmapsto Acceleration=\dfrac{10-15}{0.08}$

$\\ \sf\longmapsto Acceleration=\dfrac{-5}{0.08}$

$\\ \sf\longmapsto Acceleration=-62.5m/s^2$

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Volcanic eruptions can destroy propertics and kill people<br><br>TRUE OR FALSE

Katena32 [7]

Answer:

True

Explanation:

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I hope this helps!

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2 years ago

I don't understand how to find the frequency and period of wavelengths. Can anyone help me?

nordsb [41]

Frequency of a wave =

   (speed of the wave) divided by (wavelength)
or
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2 years ago

A fatigue test was conducted in which the mean stress was 50 MPa (7250 psi) and the stress amplitude was 225 MPa (32,625 psi).

Tems11 [23]

Answer:

275 MPa, -175 MPa

-0.63636

450 MPa

Explanation:

$\sigma_{max}$ = Maximum stress

$\sigma_{min}$ = Minimum stress

$\sigma_m$ = Mean stress = 50 MPa

$\sigma_a$ = Stress amplitude = 225 MPa

Mean stress is given by

$\sigma_m=\frac{\sigma_{max}+\sigma_{min}}{2}\\\Rightarrow \sigma_{max}+\sigma_{min}=2\sigma_m\\\Rightarrow \sigma_{max}+\sigma_{min}=2\times 50\\\Rightarrow \sigma_{max}+\sigma_{min}=100\ MPa\\\Rightarrow \sigma_{max}=100-\sigma_{min}$

Stress amplitude is given by

$\sigma_a=\frac{\sigma_{max}-\sigma_{min}}{2}\\\Rightarrow \sigma_{max}-\sigma_{min}=2\sigma_a\\\Rightarrow \sigma_{max}-\sigma_{min}=2\times 225\\\Rightarrow \sigma_{max}-\sigma_{min}=450\ MPa\\\Rightarrow 100-\sigma_{min}-\sigma_{min}=450\\\Rightarrow -2\sigma_{min}=350\\\Rightarrow \sigma_{min}=-175\ MPa$

$\sigma_{max}=100-\sigma_{min}\\\Rightarrow \sigma_{max}=100-(-175)\\\Rightarrow \sigma_{max}=275\ MPa$

Maximum stress level is 275 MPa

Minimum stress level is -175 MPa

Stress ratio is given by

$R=\frac{\sigma_{min}}{\sigma_{max}}\\\Rightarrow R=\frac{-175}{275}\\\Rightarrow R=-0.63636$

The stress ratio is -0.63636

Stress range is given by

$\sigma_{max}-\sigma_{min}=450\ MPa$

Magnitude of the stress range is 450 MPa

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2 years ago

Define the focus of a concave lens

Sophie [7]

Answer:

<u>Principal</u><u> </u><u>focus</u><u> </u><u>of</u><u> </u><u>concav</u><u>e</u><u> </u><u>lens</u><u> </u><u>-</u><u> </u>

★ The point at which rays parallel to principal axis coming from infinity appear to converge after being refracted from concave lens is called the principal focus of concave lens.

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• <u>Additional</u><u> information</u><u> </u><u>-</u><u> </u>

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Oliga [24]

Explanation:

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2 years ago