Simple R Code for high school project

Hello Im new to R and am needing help with the code - I know it sounds easy and I can do it in excel but as Im new to R the code is tricky.

I need to follow a a normal distribution (Life between 2 points) with the top = 6000 hours ,and bottom =600 hours.
I need to find the probability that a single randomly item will last less than 2000hours.
and then
I need to find the probability that the mean lifetime of a random sample is less than 2000 hours.
I can do the mean because that is easier than my knowledge, I need to know the distribution?

thanks you

Normal distributions don't have tops and bottoms, they stretch from minus infinity to plus infinity.

But see if the function pnorm() helps.