How much heat does it take to raise the temperature of 7.0 kg of water from
2 answers:
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Answer:
The coefficient of kinetic friction is 0.382.
Explanation:
Given:
Angle of inclination is, °
Mass of package is,
Initial speed of package is,
Final speed of the package at the bottom is,
Distance of travel along the incline is,
Acceleration due to gravity is,
Let the coefficient of kinetic friction be .
Now, the frictional force will be acting along the incline but in the direction opposite to the direction of motion.
So, the net acceleration acting on the package will be up the incline and is equal to:
----------------- 1
Now, using equation of motion, we have:
Solving for 'a', we get:
Now, plug in the value of 'a' in equation (1). This gives,
( Neglecting negative sign)
Plug in all the given values and solve for . This gives,
Therefore, the coefficient of kinetic friction is 0.382.
Answer:
Vi = 32 [m/s]
Explanation:
In order to solve this problem we must use the following the two following kinematics equations.
The negative sign of the second term of the equation means that the velocity decreases, as indicated in the problem.
where:
Vf = final velocity = 8[m/s]
Vi = initial velocity [m/s]
a = acceleration = [m/s^2]
t = time = 5 [s]
Now replacing:
8 = Vi - 5*a
Vi = (8 + 5*a)
As we can see we have two unknowns the initial velocity and the acceleration, so we must use a second kinematics equation.
where:
d = distance = 100[m]
(8^2) = (8 + 5*a)^2 - (2*a*100)
64 = (64 + 80*a + 25*a^2) - 200*a
0 = 80*a - 200*a + 25*a^2
0 = - 120*a + 25*a^2
0 = 25*a(a - 4.8)
therefore:
a = 0 or a = 4.8 [m/s^2]
We choose the value of 4.8 as the acceleration value, since the zero value would not apply.
Returning to the first equation:
8 = Vi - (4.8*5)
Vi = 32 [m/s]