Question

Help and explain please

Answer 1

Answer: a) Moment = 200N.m

b) F = 500N

Step-by-step explanation: Moment or Torque is the tendency of a body to rotate because of an aplplied force. It can be calculated as

`\tau = F.r.sin\theta`

F is force applied

r is distance from the force to the point of rotation

θ is the angle formed between force and distance

a) Since F and r are perpendicular, θ=90°, sin90° = 1, so

`\tau=F.r`

`\tau=100(2)`

`\tau=` 200

Torque caused by weight of the barrier at the pivot is 200N.m

b) Counterweight has the same torque as pivot:
`\tau=` 200

So, to find Force necessary to balance the weight:

`\tau=F.r`

`F=(\tau)/(r)`

`F=(200)/(0.4)`

F = 500

It is necessary a force of 500N from the counterweight to balance the weight.