Hi there, I have been trying to collect 100 coins in the clock world but have failed many times. Can everything be stopped in the game to get all the coins or do they have to be moving? Is there an easy way to get all of the coins?

It's possible to do it with the clock stopped, which makes it easier to get the red coins - but you need expert skill at wall jumping to get to the top of the clock.

From my FAQ: This is hard; you'll have to search everywhere, and make sure you get all the
blue coins, which is pretty easy. Enter with the hand on 3. Kill the two Bob -
Ombs and get their coins, then get all 10 coins in the ! box by the heart; if
you can get 2 of the red coins (possible if agile), then head up the clock
getting any coins on the way. Before you reach the second heart, head towards
*2, but use the blue coin switch instead; the Blue Coins are easy to get as
long as you don't fall (if you do, start over). Continue up, passing the three
rotating platforms, and long jump to some more coins above *5. Continue again
and get the coins above the four wall monsters. You will probably be nearly
finished, so there is one ! box ahead, then two by where you get the second
hand (one has coins, the other a 1 up). There are also coin boxes under the
Thwomp and in the platform in the middle (long jump to this).