Explanation:
Given parameters:
Mass of the weight = 15kg
Height of bar lift = 0.25m
Number of times lifted = 15times
Unknown:
Total height the bar was lifted = ?
Force needed for the lift = ?
Work done = ?
Solution:
To solve this problem we need to understand that;
Work done = Force x distance
Work done = mass x acceleration due gravity x height
Work done = weight x height
a. Total height:
Total height = 0.25 x 15 = 3.75m
b. Force needed ;
Force needed = Weight of bar = mass x gravity
= 15 x 9.8 = 147N
So;
Force used for the 15 times = 15 x 147 = 2205N
c. Work done ;
Work done = weight x height = 2205 x 3.75 = 8268.75J
