A 1500 kg car is parked at the top of a hill 5.2 m high. At the bottom of the hill, what is the kinetic energy, in Joules, of th
1 answer:
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Answer:
a. Vf = 39.24 [m/s]
b. Vf = 31.24 [m/s]
c. Vf = 47.24 [m/s].
Explanation:
To solve this problem we can use the following equation of kinematics. We have to keep in mind that the gravitational acceleration acts downwards, therefore when the rock falls towards the abyss it has the same direction of the acceleration and that is why the gravitational acceleration has a positive sign in the equation.
where:
Vf = final velocity [m/s]
Vo = initial velocity = 0 (when the rock is dropped)
g = gravitational acceleration = 9.81 [m/s²]
t = time = 4 [s]
a.
b.
In this particular situation, the acceleration will be taken as negative because the gravity is pointing in the opposite direction of the movement of the rock.
The negative sign in the answer tells us that the rock no longer moves up instead it does downwards when 4 seconds have passed.
c.
Answer:
a) Q = 80,000 cal
b) Q = 100,000 cal
c) Q = 540,000 cal
d) Q = 720,000 cal
Explanation:
a)1 kg from 0⁰ Ice to 0⁰ water, the heat produced is latent heat of fusion
= 1 * 80
= 80 kCal = 80,000 cal
b) 1 kg of O°C ice water to 1 kg of 100°C boiling water
Specific heat capacity, c = 1000cal/kg.C
c) 1 kg of 100°C boiling water to 1 kg of 100°C steam
Latent heat of vaporization is needed for this conversion
d) 1 kg of O°C ice to 1 kg of 100°C steam.
Q =
Q = 80,000 + 100,000 + 540,000
Q = 720,000 cal