Answer:
Step-by-step explanation:
Work is said to be done when a force applied to an object cause the body to move in a specified direction.
Work-done = Force * Distance
Since Force = mass * acceleration due to gravity
Work-done = mass * acceleration due to gravity * distance
Given mass = 1.4kg, distance = 0.7m and g = 9.8m/s²
Workdone in lifting the book off the floor = 1.4*0.7*9.8
Workdone = 9.604Joules
- Similarly, work done in lifting a 21-lb weight book 6 ft off the ground is expressed using the same formula as above;
Given mass = 21-lb, g = 32ft/s² and distance = 6ft
Workdone = 21 * 32 * 6
Workdone = 4,032 lb-ft²/s²
Hence, work-done in lifting a 21-lb weight book 6 ft off the ground is 4,032 lb-ft²/s²
