What caused the cable to break during the lifting of a 4500kg container?

AI Thread Summary
The investigation into the cable break during the lifting of a 4500kg container indicates that the cable's maximum tension capacity is 50,000N. Calculations show that the tension experienced during the lift was 48,645N, which is below the cable's safety rating, suggesting the load was not too heavy. The crane's specifications for speed and acceleration were adhered to, confirming it was not defective. Further analysis indicates that the cable must have been defective, as it failed under conditions that should have been safe. The conclusion is that the cable's integrity was compromised, leading to the accident.
ixbethxi
Messages
13
Reaction score
0
You've been called to investigate an accident in which a cable broke while lifting a 4500kg container. The steel cable is 2.0cm in diameter and has a safety rating of 50,000N. The crane is designed not to exceed speeds of 3.0m/s or accelerations of 1.0m/s^2, and your tests find the crane is NOT defective. what is your conclusion? did the crane operator life too heavy a load or was the cable defective.

can someone check my solution? i don't know if its right

the max tension the cable can hold is 50,000N

T-((4500kg)*(9.81m/s/s))=4500(1.0m/s/s)

T= 48,645<50,000 which means the cable must of been broken because it could possibly hold more.
 
Physics news on Phys.org
What about speed, vertical or horizontal?
 
ixbethxi said:
You've been called to investigate an accident in which a cable broke while lifting a 4500kg container. The steel cable is 2.0cm in diameter and has a safety rating of 50,000N. The crane is designed not to exceed speeds of 3.0m/s or accelerations of 1.0m/s^2, and your tests find the crane is NOT defective. what is your conclusion? did the crane operator life too heavy a load or was the cable defective.

can someone check my solution? i don't know if its right

the max tension the cable can hold is 50,000N

T-((4500kg)*(9.81m/s/s))=4500(1.0m/s/s)

T= 48,645<50,000 which means the cable must of been broken because it could possibly hold more.

Yes. You are somehow right.

If u were to work out the acceleration allowed to lift the weight. 50000-(4500*9.81)= 4500a By working out a, u will get the max acceleration allowed for the lifting of the mass. From there, you can see that the acceleration is more than that of those specified in the qn. Thus, its not that the mass is too heavy but its due to the defective cable.
 
ixbethxi said:
... and your tests find the crane is NOT defective. what is your conclusion?...
 
i concluded that it waas the cable that was defective
 
Thread 'Variable mass system : water sprayed into a moving container'
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top