Match the synthetic materials with the processes used to make them.

300 grams of ethanol is heated with 14640 Joules of energy to reach a final temperature of 30 °C. What was the initial temperatu

levacccp [35]

Answer:

10 °C

Explanation:

Applying

q = cm(t₂-t₁)............... Equation 2

Where q = heat energy, c = specific heat of ethanol, m = mass of ethanol, t₁ = initial temperature, t₂ = Final temperature.

Given: c = 2.44 J/g.°C, m = 300 g, q = 14640 J, t₂ = 30°C

Substitute into equation 2 and solve for t₁

14640 = 2.44×300(30-t₁)

14640 = 732(30-t₁)

732(30-t₁) = 14640

(30-t₁) = 14640/732

(30-t₁) = 20

t₁ = 30-20

t₁ = 10 °C

6 0

3 years ago

Read 2 more answers

If a ball is thrown vertically upward from the roof of 32 foot building with a velocity of 64 ft/sec, its height after t seconds

stepan [7]

Answer:

a) $s_{max} = 96\,ft$ , b) $v(4.449\,s) = -78.368\,\frac{ft}{s}$

Explanation:

a) The maximum height is obtained with the help of the First and Second Derivative Tests:

First Derivative

$v(t) = 64 - 32\cdot t$

$64 - 32\cdot t = 0$

$t = 2\,s$

Second Derivative

$a(t) = -32$ (absolute maximum)

The maximum height reached by the ball is:

$s (2\,s) = 32 + 64\cdot (2\,s) - 16\cdot (2\,s)^{2}$

$s_{max} = 96\,ft$

b) The time required by the ball to hit the ground is:

$32+64\cdot t - 16\cdot t^{2} = 0$

$-16\cdot (t^{2}-4\cdot t - 2) = 0$

$t^{2}-4\cdot t - 2 = 0$

$(t -4.449)\cdot (t+0.449)\approx 0$

Just one root offers a solution that is physically reasonable:

$t = 4.449\,s$

The velocity of the ball when it hits the ground is:

$v(4.449\,s) = 64 - 32\cdot (4.449\,s)$

$v(4.449\,s) = -78.368\,\frac{ft}{s}$

6 0

3 years ago

Read 2 more answers

A truck covers 40.0 m in 7.45 s while uniformly slowing down to a final velocity of 3.50 m/s.

astra-53 [7]

Answer:

(A) Original velocity will be 7.244 m /sec

(B) Acceleration will be $-0.5026m/sec^2$

Explanation:

We have given distance covers by truck s = 40 m

Time taken by truck to cover this distance t = 7.45 sec

Final velocity v = 3.50 sec

According to second equation of motion

$S=ut+\frac{1}{2}at^2$

$40=u\times 7.45+\frac{1}{2}\times a\times 7.45^2$

$7.45u+27.751a=40$ -----eqn 1

According to first equation of motion

v = u + at

So $3.5=u+7.45a$ -----eqn2

Solving equation 1 and 2

a = $-0.5026m/sec^2$

And u = 7.244 m /sec

(A) Original velocity will be 7.244 m /sec

(B) Acceleration will be

$-0.5026m/sec^2$

6 0

4 years ago

Doubling the voltage in a circuit doubles the current if what is held constant?

antiseptic1488 [7]

The Resistance needs to be the same to allow the current to double with the voltage.

4 0

4 years ago

You drive your car from home at an

kondaur [170]

Answer:

60 km/h

Explanation:

In the first part of the trip, the speed is

v = 80 km/h

while the time interval is

t = 3 h

So, the distance covered is:

d = vt = (80)(3)= 240 km

The problem states that this distance is half distance between home and the destination - so, the total distance between home and the destination is

$D=2d=2(240)=480 km$

The time taken to cover the second part of the trip is 5 h, so the total time taken is

T = 3 h + 5 h = 8 h

Therefore, the average velocity for the entire trip is

$v=\frac{D}{T}=\frac{480}{8}=60 km/h$

3 0

3 years ago