Compute the muscle force and disk compressive force for two different lifting methods. Which method is safer to lift?

a. Muscle (erector spinae) moment arm is 2 in.
b. Weight of the box is 40 lbs.
c. Horizonal moment-arm (from lumbar spine to the box) for the first and second methods are 20 inch and 18 inch, respectively.

Free runners jump long distances and land on the ground or a wall. how do they apply newton’s second law to lessen the force of impact?

Explain why you think this diagram shows what happened to the carbon in the biodome.

Two point charges are separated by a certain distance. how does the strength of the electric field produced by the first charge, at the position of the second charge, change if the second charge is doubled? a. the field does not change b. the field strength decreases by half. c. the field strength doubles d. the field strength quadruples