Answer:
15km/h East (15m/s East option)
Explanation:
Velocity = (change in) Distance/(change in) Time
The distance here is 60km, and the time is 4h, as given by the question. Therefore the velocity is 60km/4h = 15km/h.
To convert km/h to m/s, we just divide the value by 3.6, 15/3.6= 4.17m/s (2dp), which isn't actually an option here, so I'm assuming maybe a mistake in unit for the question?
'Velocity' is a vector quantity, meaning it has a size<em> </em>and a direction, as opposed to speed, a scalar quantity, which only has size. Therefore we need to add a direction for it to be velocity. The given direction here is east, so the velocity of the car is 15km/h East. (I would choose the 15m/s East as the question likely has a unit error and is closest.)
Hope this helped!
Explanation:it is beause they are sharper and also have less surface area and therefore more pressure
Answer:

Explanation:
The gravitational potential energy gets transformed into translational and rotational kinetic energy, so we can write
. Since
(the ball rolls without slipping) and for a solid sphere
, we have:

So our translational speed will be:

They can pretty much be by water i think