Where does Elizabeth want John to do and what does she want him to do there?

The acceleration of a point is given. a = 20 t m/s2 When t=0, s = 50 m and v = -8 m/s. What are the position and velocity of the

lidiya [134]

Answer:

v=82 m/s

s=116m

Explanation:

a=20t

$\frac{\mathrm{d} v}{\mathrm{d} t}=20t\\\int\limits dv =\int(20t) dt\\v={10}t^2+c$

using condition given at t=0

$-8=10\times 0^2 +c$

c=-8

now equation becomes

v=10t²-8

v at t= 3s v=82 m/s

again

$\frac{\mathrm{d} s}{\mathrm{d} t}=10t^2-8$

$ds=(10t^2-8)dt\\\int\limits ds =\int(10t^2-8) dt\\s=\frac{10}{3} t^2-8t+b$

now using condition given s=50 at t=0

b=50

now equation becomes

$s=\frac{10}{3}t^3-8t+50$

calculating s at t=3s

s=116m

6 0

3 years ago

A steam power plant with a power output of 230 MW consumes coal at a rate of 60 tons/h. If the heating value of the coal is 30,0

NARA [144]

Answer:

$\eta =46\%$

Explanation:

Hello!

In this case, we compute the heat output from coal, given its heating value and the mass flow:

$Q_H=60\frac{tons}{h}*\frac{1000kg}{1ton}*\frac{1h}{3600s}*\frac{30,000kJ}{kg}\\\\Q_H=500,000\frac{kJ}{s}*\frac{1MJ}{1000J} =500MW$

Next, since the work done by the power plant is 230 MW, we compute the efficiency as shown below:

$\eta =\frac{230MW}{500MW}*100\% \\\\\eta =46\%$

Best regards!

7 0

3 years ago

A hollow pipe is submerged in a stream of water so that the length of the pipe is parallel to the velocity of the water. If the

Arlecino [84]

Answer:

increases by a factor of 6.

Explanation:

Let us assume that the initial cross sectional area of the pipe is A m² while the initial velocity of the water is V m/s², hence the flow rate of the water is:

Initial flow rate = area * velocity = A * V = AV m³/s

The water speed doubles (2V m/s) and the cross-sectional area of the pipe triples (3A m²), hence the volume flow rate becomes:

Final flow rate = 2V * 3A = 6AV m³/s = 6 * initial flow rate

Hence, the volume flow rate of the water passing through it increases by a factor of 6.

8 0

3 years ago

What is the hardest part of engineering?

Vikki [24]

ANSWER:

Aerospace Engineering. ...

Chemical Engineering. ...

Biomedical Engineering.

EXPLANATION:

This is all i know but ... I hope this helps~

7 0

2 years ago

A large plate is fabricated from a steel alloy that has a plane strain fracture toughness of 78 MPa (70.98 ksi). If the plate is

Reika [66]

Answer:

minimum length of a surface crack is 15.043 mm

Explanation:

given data

strain fracture toughness K = 78 MPa

tensile stress = 345 MPa

Y = 1.04

to find out

minimum length of a surface crack

solution

we find here length of critical interior flaw from formula that is

α = $\frac{1}{\pi} (\frac{K}{\sigma Y})^2$ ....................1

put here value we get

α = $\frac{1}{\pi} (\frac{78*\sqrt{10^3} }{345*1.04})^2$

α = 15.043 mm

so minimum length of a surface crack is 15.043 mm

7 0

3 years ago

Where does Elizabeth want John to do and what does she want him to do there?​

Where does Elizabeth want John to do and what does she want him to do there?