Impending motion vs start to slide

[goldfish9776]

Homework Statement

what is the difference between the first and second question ? aren't they the same ?

Homework Equations

The Attempt at a Solution

 

[BvU]

To me they are. What a strange block this is! More than 300 m high and only 50 kg !
This a real exercise in a real book or some kind of garbled home-made thingy ?

 

[TSny]

There is another type of motion that you can investigate other than sliding, namely tipping. That might be what part (a) is referring to.

It appears to me that the answers are switched. The answer listed for (b) seems to be the answer for (a) if you assume no sliding and only tipping.

The problem is odd. I don't think the block can be on the verge of tipping without also sliding.

 

[goldfish9776]

There is another type of motion that you can investigate other than sliding, namely tipping. That might be what part (a) is referring to.

It appears to me that the answers are switched. The answer listed for (b) seems to be the answer for (a) if you assume no sliding and only tipping.

The problem is odd. I don't think the block can be on the verge of tipping without also sliding.

well , what s the condition for tipping ?

 

[BvU]

Your call ! At what angle does the thing keel over ?