do economiists use the term investment to signify physical or mental work
Both
physical because you interact with things
They both need physical and mental concentration.
Both mental and physical activities require energy, but they affect the body in different ways. Mental work can be taxing on the brain and may lead to fatigue, while physical work uses energy to move muscles and may lead to physical exhaustion. The amount of energy used depends on the type and intensity of the activity.
labour usually means physical or mental work or exertion.
Work is the physical or mental effort exerted to achieve a specific result, typically for the purpose of earning a living or achieving a goal. It involves the application of energy over time to accomplish a task or produce a desired outcome.
You can say "mental and physical health". You can also say "physical and mental health". So both are completely acceptable.
the hours are 9:00Am - 3:30
Activity involving mental or physical effort to get some money. Example: he came late on work.
Whenever you can, but preferably when you have the most mental and physical energy and that is dependent on the person.
mental