Explanation:
a) The process can be modeled as an adiabatic compression, because the pulses of pressurized air is governed into the tire and time frame is very small for any heat transfer through the tires. Hence, Q_net = 0.
The first law of thermodynamics states that the change in the internal energy is ∆U=Q-W= -W, since Q_net = 0 for adiabatic processes. Work is being done on the system by pumping action hence W_net is negative; therefore the change in the internal energy, ∆U, is positive. Since ∆U, is a function of initial and final temperatures the final final temperature must increase for ∆U to be positive.
b) The process can be modeled as an adiabatic expansion when a highly pressurized mixture of air and water is released into atmosphere from 20 atm to 1 atm. The time frame is very small for any heat transfer through the mixture. Hence, Q_net = 0.
The first law of thermodynamics states that the change in the internal energy is ∆U=Q-W= -W, since Q_net = 0 for adiabatic processes. Work is being done by the mixture on its surroundings due to change in pressure from high to low. The W_net is positive; therefore the change in the internal energy, ∆U, is negative. Since ∆U, is a function of initial and final temperatures the final final temperature must decrease for ∆U to be negative. The final temperatures drops below freezing point due to sudden adiabatic expansion of mixture leads to formation of snow.
Time dilation is the slowing of the passage of time at high speeds. The faster the object moves, the greater the amount of time dilation. Time dilation, in part, accounts for the constant speed of light, regardless of the light's source and regardless of the observer's perspective.
Answer:
Electricity works by getting a bunch of conductor elements together and creating a flow of electron-stealing patterns through them. This flow is called a current. Conductors need to be surrounded with insulators so the electrons can only go in one direction.
Explanation:
Answer: option B. 45°
Explanation:
A body thrown at an angle from horizontal undergoes a projectile motion. The maximum horizontal displacement means the maximum range covered. The range is given by:
where v is the initial velocity, is angle of the projectile and g is the acceleration due to gravity.
For maximum range, sin 2θ = 1
2θ = sin⁻¹ 1 = 90°
θ = 90°/2 = 45°
Thus, the projectile undergoes maximum horizontal displacement at angle of 45°. Correct option is B.
Answer: 6.48m/s
Explanation:
First, we know that Impulse = change in momentum
Initial velocity, u = 19.8m/s
Let,
Velocity after first collision = x m/s
Velocity after second collision = y m/s
Also, we know that
Impulse = m(v - u). But then, the question said, the guard rail delivered a "resistive" impulse. Thus, our impulse would be m(u - v).
5700 = 1500(19.8 - x)
5700 = 29700 - 1500x
1500x = 29700 - 5700
1500x = 24000
x = 24000/1500
x = 16m/s
Also, at the second guard rail. impulse = ft, so that
Impulse = 79000 * 0.12
Impulse = 9480
This makes us have
Impulse = m(x - y)
9480 = 1500(16 -y)
9480 = 24000 - 1500y
1500y = 24000 - 9480
1500y = 14520
y = 14520 / 1500
y = 9.68
Then, the velocity decreases by 3.2, so that the final velocity of the car is
9.68 - 3.2 = 6.48m/s