Land surfaces change, erosion happens, the ground collapses, etc.
Distance , d = a+b

The unit of d is in meter and t is in seconds.
So the unit of a a must be meter.
Now we have unit of b

is meter.
So unit of b*

= meter
Unit of b = meter/

So unit of a = m and unit of b = m/

.
Answer: 60
Explanation: if u hit it it will have impact and the impact added 10n
If I drop my egg unprotected, then it will break.