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1 year ago

A fast Humvee drove from desert A to desert B. For the first 12

Physics

1 answer:

Zina [86]1 year ago

4 0

Answer:

v = 172 km/h

Explanation:

For the first 12 hours, it traveled at an average speed of 185 km/h. Let d₁ is distance. So,

$d_1=v_1\times t_1\\\\d_1=185\ km/h\times 12\ h\\\\d_1=2220\ km$

For the next 13 hours, it traveled at an average speed of 160 km/h. Let d₂ is the distance. So,

$d_2=v_2\times t_2\\\\d_2=160\ km/h\times 13\ h\\\\d_2=2080\ km$

Average speed = total distance/time taken

So,

$v=\dfrac{d_1+d_2}{t_1+t_2}\\\\v=\dfrac{2220+2080}{12+13}\\\\v=172\ km/h$

So, the average speed of the whole journey is 172 km/h.

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A blacksmith heats a 1,540 g iron horseshoe to a temperature of 1445°c before dropping it into 4,280 g of water at 23.1°c. if th

Marta_Voda [28]

Given:
m₁ = 1540 g, mass of iron horseshoe
T₁ = 1445 °C, initial temperature of horseshoe
c₁ = 0.4494 J/(g-°C), specific heat

m₂ = 4280 g, mass of water
T₂ = 23.1 C, initial temperature of water
c₂ = 4.18 J/(g-°C), specific heat of water
L = 947,000 J heat absorbed by the water.

Let the final temperature be T °C.
For energy balance,
m₁c₁(T₁ - T) = m₂c₂(T - T₂) + L
(1540 g)*(0.4494 J/(g-C))*(1445-T C) = (4280 g)*(4.18 J/(g-C))*(T-23.1 C) + 947000 J
692.076(1445 - T) = 17890(T - 23.1) + 947000
10⁶ - 692.076T = 17890T - 413259 + 947000
466259 = 18582.076T
T = 25.09 °C

Answer: 25.1 °C

3 0

1 year ago

Question 5 At 12:00 pm, a spaceship is at position ⎡⎣324⎤⎦ km ⎣ ⎢ ⎡ 3 2 4 ⎦ ⎥ ⎤ km away from the origin with respect to so

Anettt [7]

Answer:

[1, 6, -2]

Explanation:

Given the following :

Initial Position of spaceship : [3 2 4] km

Velocity of spaceship : [-1 2 - 3] km/hr

Location of ship after two hours have passed :

Distance moved by spaceship :

Velocity × time

[-1 2 -3] × 2 = [-2 4 -6]

Location of ship after two hours :

Initial position + distance moved

[3 2 4] + [-2 4 -6] = [3 + (-2)], [2 + 4], [4 + (-6)]

= [3-2, 2+4, 4-6] = [1, 6, -2]

4 0

1 year ago

Which of the following substances will show the smallest change in temperature when equal amounts of energy are absorbed?

SSSSS [86.1K]

It would be water because if you freeze it than you will still be able to see it and if you boil it than you will be able to see it disappear.

3 0

1 year ago

Read 2 more answers

A 4 kg box is on a frictionless 35° slope and is connected via a massless string over a massless, frictionless pulley to a hangi

Anarel [89]

Answer:

(a) 19.62 N

(b) Box moves down the slope

Explanation:

(a)

2 Kg box causes tension

$T=mgwhere m is mass, g is gravitational force taken as 9.81T=2*9.81 =19.62 N (b) Block mass of 4 Kg [tex]T'-mg sin \theta=0$ hence $T'=mg sin \theta$ where m is mass and g is gravitational force

T'=4*9.81 sin 35= 22.5071 N

Since T' is greater than $mg sin\theta$ , then the box moves down the slope

(c)

Acceleration a= $\frac {forward force-backward force}{Total mass}= \frac {mg sin \theta -mg}{m1 + m2}$

$a= \frac {22.51-19.62}{2+4}=0.48$

When moving, the box will exert force T"= $mgsin \theta + ma$

T"= 4*9.81 sin 35 +(4*0.48)= 24.43 N

7 0

1 year ago

Read 2 more answers

Air "breaks down" when the electric field strength reaches 3×106n/c, causing a spark. a parallel-plate capacitor is made from tw

aalyn [17]

Ok, I think this is right but I am not sure:
Q = ϵ
0AE
A= π π
r^2

=(8.85x10^-12 C^2/Nm^2)
( π π (0.02m)^2)
(3x10^6 N/C) =3.3x10^-8 C = 33nC N = Q/e = (3.3x10^-8 C)/(1.60x10^-19 C/electron) = 2.1x10^11 electrons

4 0

1 year ago