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ollegr [7]
2 years ago
12

The energy change in an endothermic reaction is: A. Internal B. External C. Negative D. Positive

Physics
1 answer:
77julia77 [94]2 years ago
4 0

Answer:

Positive

Explanation:

In an endothermic reaction, the products are at a higher energy than the reactants. This means that the enthalpy change of the reaction (∆H) is positive

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Rafael is driving his car at 26 m/s. What is the shortest distance in which he can brake and stop if the coefficient of static f
Hitman42 [59]

Answer:

86.14 meters.

Explanation:

Step one:

Given data

velocity of car = 26 m/s

the coefficient of static friction between the tires and the road

µ = 0.4 (kinetic)

Let us take g = 9.81 m/s^2

Required

The distance x = distance in m

We know that

N = Fg = mg\\\\F_\mu  = -\mu N = \mu F_g = \mu mg\\\\KE = (1/2) mv^2

W = F*x  (Work is force times distance)

Step two:

Conservation of energy gives  

KE = W

Substituting gives  

(1/2) mv^2 = F \mu x\\\\(1/2) mv^2 = \mu mgx\\\\mv^2 = 2 \mu mgx

Solving for distance (x) gives  

x = mv^2  / 2 \mu mg

Simplifying

x = v^2 / 2 \mu g

Substitute:  

x = v^2 / 2 \mu g

x= 26^2/2*0.4*9.81

x=676/7.848\\\\x=86.14

Therefore, the minimum braking distance is 86.14 meters.

4 0
3 years ago
Which property of the sound wave changes when the volume is increased on a radio?.
ch4aika [34]

Answer:

amplitude

Explanation:

When we increase the volume of a sound, the amplitude of the wave is increased. The frequency of a wave is related to its pitch. If the pitch is high, then the frequency of the wave is high. This means that the wave will looked squashed on an oscilloscope trace.

8 0
2 years ago
Newton's first law of motion is also called the law of acceleration true or false
kotykmax [81]
False. Newton first is also called the law of intertia
4 0
3 years ago
Two people, one of mass 85 kg and the other of mass 50 kg, sit in a rowboat of mass 90 kg. With the boat initially at rest, the
sergeinik [125]

Answer:

0.11m

Explanation:

let's assume the boat is of uniform construction

Ignoring friction losses

Also assume the origin is at the end of the boat originally with the heavier person

the center of mass of the whole system will not change relative to the water when the two swap ends

Originally, the center of mass is

85[0] + 90[3.5/2] + 50[3.5] / (85 + 90 + 50) = 1.14m from the origin

after the swap, the center of mass is

50[0] + 90[3.5/2] + 85[3.5] / (85 + 90+ 50) = 1.030m from the origin

The center of mass has shifted

1.14-1.030 = 0.11m

as no external force acted on the system, the center of mass relative to the water will not change. The boat will therefore shift towards the end where the heavier person originally sat

4 0
3 years ago
Physics conversion <br> Convert 300 cm/min^2 into m/s^2 <br> Please give a thorough explanation!
ANTONII [103]

Answer:

8.33×10⁻⁴ m/s²

Explanation:

There are 100 cm in 1 m, and 60 s in 1 min.

300 cm/min² × (1 m / 100 cm) × (1 min / 60 s)² = 8.33×10⁻⁴ m/s²

6 0
3 years ago
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