Activity 3

Problem 1.

A slide has a 5 m long bar and over the bar are seated two people. One of them weights 60 kg. and the other one 40 kg. Calculate the position of the fulcrum to equilibrate the slide

Problem 2.

This mechanism is used to tap wine bottles as it is represented in the picture. If we need 50 N force to tap the bottle, which is the force P that has to be applied?

Solution

Apply Lever's law

F x Force arm = Load x Load Arm

P x 50 cm = L x 20 cm

P x 50 cm = 50 N x 20 cm

P = 20 N

Problem 3.

This mechanism is designed to lift 4Tn weight . Calculate the force that has to be applied in the piston

Transform load to a force

L = m x g

L = 4000 kg x 10 m/s2

L= 40.000 N

Apply lever's law

F x Force arm = L X Load Arm

F x 1 m = 40.000 x 3 m

F = 120.000 N

Problem 4.

Calculate the force that we have to do (R) with this combined levers mechanisms if we want to lift a weight of 6 N. Calculate also, the mechanical advantage.

Apply lever's law in the upper lever to calculate F

6 x 5 cm = F x 15 cm

F= 30/15

F= 2N

Apply lever's law in the second lever

2 x 5 cm = R' x 15 cm

R' = 10/15

R= 0,33 N