Question

1. A 2m long crow bar is used to displace a heavy stone. If the fulcrum is placed at a distance of 40 cm from the load .Find it's mechanical advantage

2.What is the efficiency of a simple machine which has velocity ratio 4 and mechanical advantage 3? What effort is necessary to lift 30N load in machine?

please show the process also
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Answer 1

Answer:

1 Length of crow bar = 2m

length of load arm = 0.1M

length effort arm = length of crow bar -length of load arm

=2−0.1=1.9m

so, velocity ratio = length of effort arm/length of load arm = 1.9/0.1 = 19

use formula, velocity ratio = load/effort

19 = 100kgf/effort

effort = 100/19= 5.26 kgf

hence,5.26 effort is required.

2 I don't no