Question

A crowbar of length 45 cm is used to lift up a rock weighing 16 kg from the ground, if the fulcrum is 5cm from the rock, what is the effort needed?( in kgf)​

Answer 1

Explanation:

length of crow bar =2m

length of load arm = 0.1 m

length of effort arm equals length of crowbar-length of load arm

=2-0.1=1.9m

so velocity ratio=length length of a effort

arm /length of load arm=

$\frac{1.9}{0.1} = 19$

velocity velocity ratio =load /effort

$19 = 100kgf \div effort$

$effort = \frac{100}{19} = 5.26kgf$

$hence \: 5.26 \: effort \: is \: reqired$

Answer 2

Explanation:

length of crow bar =2m

length of load arm = 0.1 m

length of effort arm equals length of crowbar-length of load arm

=2-0.1=1.9m

so velocity ratio=length length of a effort

arm /length of load arm=

$\frac{1.9}{0.1} = 19$

velocity velocity ratio =load /effort

$19 = 100kgf \div effort$

$effort = \frac{100}{19} = 5.26kgf$

$hence \: 5.26 \: effort \: is \: reqired$