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3 years ago

. A driver travels 4.25 km. in two minutes. If the driver’s initial velocity is 20m/s, what is the acceleration?

Physics

1 answer:

Novosadov [1.4K]3 years ago

4 0

Answer:

32.9166667 m / s^2

Explanation:

s = 4.25km (1000m / 1km)

= 4250m

u = 20m/s

delta T = 20min (60sec / 1min)

= 1200s

Use formula s = ut + (1/2)at^2

4250m = 20m/s * 1200s + (1/2)a*1200s^2

Rearrange it to find a

a = (s-ut) / (1/2 * t^2)

a = (4250m - 20m/s*1200s) / (1/2 * 1200s^2)

a = -32.9166667 m / s^2

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Two 110 kg bumper cars are moving toward each other in opposite directions. Car A is moving at 8 m/s and Car Z at –10 m/s when t

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3 years ago

Argon gas enters steadily an adiabatic turbine at 900 kPa and 450C with a velocity of 80 m/s and leaves at 150 kPa with a veloc

Crazy boy [7]

Answer:

Temperature at the exit = $267.3 C$

Explanation:

For the steady energy flow through a control volume, the power output is given as

$W_{out}= -m_{f}(h_{2}-h_{1} + \frac{v_{2}^{2}}{2} - \frac{v_{1}^{2}}{2})$

Inlet area of the turbine = $60cm^{2}= 0.006m^{2}$

To find the mass flow rate, we can apply the ideal gas laws to estimate the specific volume, from there we can get the mass flow rate.

Assuming Argon behaves as an Ideal gas, we have the specific volume $v_{1}$

$v_{1}=\frac{RT_{1}}{P_{1}}=\frac{0.2081\times723}{900}=0.1672m^{3}/kg$

$m_{f}=\frac{1}{v_{1}}\times A_{1}V_{1} = \frac{1}{0.1672}\times(0.006)(80)=2.871kg/sec$

for Ideal gasses, the enthalpy change can be calculated using the formula

$h_{2}-h_{1}=C_{p}(T_{2}-T_{1})$

hence we have

$W_{out}= -m_{f}((C_{p}(T_{2}-T_{1}) + \frac{v_{2}^{2}}{2} - \frac{v_{1}^{2}}{2})$

$250= -2.871((0.5203(T_{2}-450) + \frac{150^{2}}{2\times 1000} - \frac{80^{2}}{2\times 1000})$

<em>Note: to convert the Kinetic energy term to kilojoules, it was multiplied by 1000</em>

evaluating the above equation, we have $T_{2}=267.3C$

Hence, the temperature at the exit = $267.3 C$

5 0

3 years ago

65. A length of wire is bent into a closed loop and a magnet is plunged into it, inducing a voltage and, consequently, a current

natulia [17]

Answer:

Resistance of the second wire is twice the first wire.

Explanation:

Let us first see the formula of resistance;

R = pxL/A

Here L is the lenght of the wire, A the area and p is the resistivity of wire.

As we are given that the length of second wire is double than that of the first wire, hence the resistance of second wire would be double.

Since we have two loop in second case, inducing double voltage but as resistance is doubled so the current would remain same according to ohms law

I = V/R

6 0

3 years ago

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