This question is incomplete, the missing diagram is uploaded along this Answer below.
Answer:
a) the work done on the cart by the spring is 4.875 lb-ft
b) the work done on the cart by its weight is - 3.935 lb-ft
Explanation:
Given the data in the question;
(a) determine the work done on the cart by the spring
we calculate the work done on the cart by the spring as follows;
= 1/2×k( - )
where k is spring constant ( 3 lb/in )
we substitute
= 1/2 × 3( (-8)² - (5)² )
= 1/2 × 3( 64 - 25 )
= 1/2 × 3( 39 )
= 58.5 lb-in
we convert to pound force-foot
= 58.5 × 0.0833333 lb-ft
= 4.875 lb-ft
Therefore, the work done on the cart by the spring is 4.875 lb-ft
b) the work done on the cart by its weight
work done by its weight;
= -mgsin∅( x₂ - x₁ )
we substitute in of values from the image below;
= -14 × sin(15°)( 5 - (-8) )
= -14 × 0.2588 × 13
= -47.1 lb-in
we convert to pound force-foot
= -47.1 × 0.0833333 lb-ft
= - 3.935 lb-ft
Therefore, the work done on the cart by its weight is - 3.935 lb-ft