Author Question: Discuss whether any work is being done by each of the following agents and, if so, whether the work ... (Read 79 times)

SGallaher96 · **on:** Jul 28, 2018

Discuss whether any work is being done by each of the following agents and, if so, whether the work is positive or negative.

(i) a chicken scratching on the ground
(ii) a person studying physics
(iii) a crane lifting a bucket of concrete
(iv) the gravitational force on the bucket in (iii)
(v) the leg muscles of a person in the act of sitting down

1.All of them do work. Positive work is done in cases (i), (ii), and (iii) and negative work is done in cases (iv) and (v).
2.No work is done in case (ii). Positive work is done in cases (i) and (iii) and negative work is done in cases (iv) and (v).
3.No work is done in cases (i) and (ii). Positive work is done in case (iii) and negative work is done in cases (iv) and (v).
4.No work is done in cases (i) and (ii). Positive work is done in cases (iii) and (v) and negative work is done in case (iv).

Question 2

You go out for a burger with some friends. At the restaurant the waiter serves you your burger on a plate. You pick up the burger with your hand and lift it to your mouth. About how much power did you expend when you lifted the burger to your mouth from the plate?
1.0.1 watts
2.1 watt
3.10 watts
4.100 watts