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emmainna [20.7K]
2 years ago
12

7. A car is travelling along a road at 30 ms when a pedestrian steps into the road 55 m ahead. The

Physics
1 answer:
trasher [3.6K]2 years ago
6 0

Answer: Car collide with man

Explanation:

Given

Speed of car is u=30\ m/s

Distance of the man from the car is s=55\ m

Reaction time t_r=0.5\ s

Rate of deceleration a_d=-10\ m/s^2

Distance traveled in the reaction time d_o=30\times 0.5=15\ m

Net effective distance to cover d=55-15=40\ m

Distance required to stop the car

\Rightarrow v^2-30^2=2(-10)(s)\\\Rightarrow 0-900=-20s\\\Rightarrow s=45\ m

Require distance is more than that of net effective distance. Hence, car collides with the man.

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PLEASE HELP ME :)
ddd [48]

A) 350 J

- The initial internal energy of the cup is

U_i = 230 J

- The final internal energy of the cup is

U_f = 580 J

According to the first law of thermodynamics:

U_f - U_i = Q+W

where

Q is the heat absorbed by the system

W is the work done on the system

The work done on the system in this case is 0, so we can rewrite the equation as

U_f - U_i = Q

And so we find the heat transferred

Q=580 J - 230 J=350 J

B) IN the cup

Explanation:

in this situation, we see that the internal energy of the cup increases. The internal energy of an object/substance is proportional to its temperature, so it is a measure of the average kinetic energy of the molecules of the object/substance. Therefore, in this case, the temperature (and the energy of the molecules of the substance) has increased: this means that heat has been transferred INTO the system from the environment (the heat came from the sun).

8 0
3 years ago
Water flows from the bottom of a storage tank at a rate of r(t) = 300 − 6t liters per minute, where 0 ≤ t ≤ 50. Find the amount
SSSSS [86.1K]

r(t) models the water flow rate, so the total amount of water that has flowed out of the tank can be calculated by integrating r(t) with respect to time t on the interval t = [0, 35]min

∫r(t)dt, t = [0, 35]

= ∫(300-6t)dt, t = [0, 35]

= 300t-3t², t = [0, 35]

= 300(35) - 3(35)² - 300(0) + 3(0)²

= 6825 liters

7 0
3 years ago
How do you find the voltage of a section of a parallel circuit?
sergiy2304 [10]

Answer: Voltage is the same across each component of the parallel circuit. The sum of the currents through each path is equal to the total current that flows from the source. You can find total resistance in a Parallel circuit with the following formula: 1/Rt = 1/R1 + 1/R2 + 1/R3 +.

Hope this helps!

3 0
3 years ago
As a raindrop falls from a cloud to the surface of Earth,
Sunny_sXe [5.5K]
The correct answer would be C. it moves at a constant speed. The troposphere(the layer our weather is in) is not nearly high enough for gravity to be different at different altitudes.
6 0
3 years ago
How does the law of conservation of mass apply to this reaction: C2H4 + O2 → H2O + CO2?
kicyunya [14]

The answer is a

the equation needs to be balanced. There are fewer oxygen atoms in the equation than hydrogen or a carbon

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3 years ago
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