a student that just received their driver's license decides to buy a new car. he remembers from physics class that heat engines
1 answer:
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Answer:
<em>60008.4 J</em>
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Explanation:
The mass of each kid = 30 kg
mass of the cart = 20 kg
The speed of the cart down the hill = 30 km/hr = 30 x 1000/3600 = 8.33 m/s
The height of the hill = 80 m
The potential energy of the boys at the top of the hill = mgh
where
m is the total mass of the kids and the cart = (30 x 2) + 20 = 80 kg
g is the acceleration due to gravity = 9.81 m/s^2
h is their height above the ground = 80 m (on the top of the hill)
substituting, we have
potential energy PE = 80 x 9.81 x 80 = 62784 J
At an instance at the bottom of the hill
their kinetic energy =
where
v is their velocity = 8.33 m/s
m is their total mass = 80 kg
substituting, we have
kinetic energy KE = = 2775.6 J
Total work done on the cart is equal to the energy lost by the cart when it reached the bottom of the hill
work done by friction = PE - KE = 62784 - 2775.6 = <em>60008.4 J</em>
Answer:
Electric field, E = 40608.75 N/C
Explanation:
It is given that,
Mass of electrons,
Initial speed of electron, u = 0
Final speed of electrons,
Distance traveled, s = 6.3 cm = 0.063 m
Firstly, we will find the acceleration of the electron using third equation of motion as :
Now we will find the electric field required in the tube as :
E = 40608.75 N/C
So, the electric field required in the tube is 40608.75 N/C. Hence, this is the required solution.
Answer:
Resistance = 68.23 Ω
Explanation:
Let's start off by remembering the fact that when resistors are connected in series, their resistances is added up to find the total resistance.
The equation for resistance using resistivity is given below:
Resistance = Resistivity * Length / Area
where Length = x
Resistivity = 3x^5
and Area = = 8.04 * 10^(-8) meter squared
Substituting in the value of resistivity, length and area we get:
Resistance =
Resistance =
Since resistance in series is added, we can simply integrate this formula over the length (x = 0 to x = 0.2) to get the total resistance.
Resistance =
Resistance =
Resistance = 68.23 Ω