- #1
hk4491
- 9
- 0
Homework Statement
A cable railway in Austria has a length of 5.6 km. The cars on the cable need 60 minutes for a whole trip along the cable. Assume that 12 cars with a payload of 550 kg are traveling upwards, and 12 empty cars are traveling downwards. The angle between the cable and the ground in 30°. What is the power generated by the motor operating the railway?
Hint: Against which outer forces does the motor have to bring the power, so that the cars start moving?
Homework Equations
P=W/t
W= F*d
The Attempt at a Solution
Can someone please tell me if the following method I used is correct?Assuming the mass of an empty car is "m", the mass of the cars going upwards will be (550 + m)
The only relevant force acting on the cars is the weight.
For the upwards traveling cars: (where Fc means the vector component on the cable)
Fc = -(550 + m)*g*cos30*12
For the downwards traveling cars:
Fc = m*g*cos30*12
After adding the two the total force would be: F= -550*g*cos30*12
Then calculating the work: W = -550*g*cos30*5,600
The power would be: P= (-550*g*cos30*5,600)/3,600 = 87,133 W = 87.1 kW