A load of 400 N is lifted by a first class lever in which the load is at the distance of 20 cm and the effort is at the distance of 60 cm from fulcrum If150 N effort is required to lift the load what is its efficiency

When an object is heated it contracts. a. true b. false

You want to lose weight and have been trying to decide which type of fad diet is best for you. you ask your doctor, who responds that a. fad diets are a temporary fix but generally don't have any side effects b. fad diets can be used several times a year to maintain a healthy weight c. fad diets can be risky for your health and, in the long run, do not work d. fad diets should never be used one right after the other; there should be a break between them select the best answer from the choices provided. a b c d

Two conductors, a and b, are each in the shape of a tetrahedron. but of different sizes. they are charged in the following manner: 1. tetrahedron a is charged from an electrostatic generator to charge q. 2. tetrahedron a is briefly touched to tetrahedron b. 3. steps 1 and 2 are repeated until the charge on tetrahedron b reaches a maximum value. if the charge on tetrahedron b was q/4 after the first time it touched tetrahedron a. what is the final charge qbmax on tetrahedron b?