Question

2

A crane has an arm to which is attached a frictionless pulley. A cable passes over the pulley and
supports a load of 10 kN as shown.
frictionless pulley
104N
30
30°
crane arm
load
10 KN
The crane arm exerts a force F on the pulley.
What is the value of F?
C
8.7 KN
10 KN
D
A
17 kN
B
5.0 KN

Answer 1

17kN

Step-by-step explanation:

The force of 10 kN in the cable and the load of 10 kN both have a component along the crane arm.

The force F exerted by the crane arm on the pulley is the sum of these 2 components.

Component of force in cable along the crane arm = 10 cos 30°

Component of load along the crane arm = 10 cos 30°

Considering the forces on the pulley,

F = 10 cos 30° + 10 cos 30°

Force F = 17.32 kN = 17 kN