Why did Weston cut a ridiculous figure? Why did Denham consider P.T. to be a waste of time?

Hint: To Sir, with Love is a work of fiction based on the author's experiences after World War II, when he went to teach in London's infamously violent East End. Ricardo Braithwaite, the main character, works as an engineer at an Aruban oil refinery before coming to England soon before WWII.

Complete answer:
To Sir, With Love is a 1959 autobiographical novel set in the East End of London by Eustace Edward Ricardo Braithwaite, often known as E. R. Braithwaite. The story is based on actual circumstances surrounding Braithwaite's appointment as a teacher in a Greenslade school. Mark, an unemployed engineer, accepts a teaching position in a secondary school in London's East End. Mark maintains his own kind of discipline in class, unaffected by the boisterous kids. After WWII, Braithwaite struggled to find a regular job. He eventually finds work as a teacher in London.

Mr Weston was questioned by the students at the Half-Year Report. Weston made a ludicrous cut. In the face of Denham's harsh criticism and Feynman’s astute interrogation, he became perplexed and attempted to bluff his way out with a show of outraged dignity. He couldn't convincingly argue that P.T. exercises, for which he was partially responsible, had any tangible bodily benefit.

Note: To Sir, with Love's major topics are education and racial discrimination. While Braithwaite overcomes the challenges he faces, a critical reader could see his attitude as egotistical, seeing societal issues as addressed if he can keep them from harming him personally.