Given values:
Mass of the steel ball, m = 100 g = 0.1 kg
Height of the steel ball, h1 = 1.8 m
Rebound height, h2 = 1.25 m
a. PE= mgh
0.1 x 9.8 x 1.8 =
1.764 Joules
b. KE = PE ->
1.764 Joules
c. KE= 1/2 mv square
so v = square root 2ke/m
square root 2 x 1.764/ 0.1
= 5.93 m/s
d. KE=PE=mgh square
0.1 x 9.8 x 1.21 =
1.186 joules
velocity of rebond is square root 2x 1.186/ 0.1 = 4.87 m/s
Since the choices are not given, I can't give an exact answer. Sublimation is the physical change occurring from solid to gas. This is very rare because the molecular arrangement of a solid and gas are opposite to each other. Thus, it depends on the properties of the substance. For example, napthalene could sublime at room temperature.
The net force is the 10N force and its direction is towards F2 force.
<h3>What is resultant force?</h3>
The resultant force or the net force is the actual force that acts on a body. We are told that the two forces act in opposite directions hence the net force is F2 - F1 = 30 N - 20 N = 10 N.
ii) The direction of this net force is going to be towards the 30N force.
iii) If the body does not move under the application of these forces then the F1 force must be reinforced by another force which balances it against the F2 force.
Learn more about net force:brainly.com/question/18031889?
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Streamline
Effect
Drag
Parachutes
Surface area
Friction
Air
Water
v = 
and
a = 
We have acceleration and velocity so:
3 = 
88.3 = 
In the acceleration equation we can isolate for v and then plug it back into the other equation to solve...
So...


Divide by three and
t = 29.4 s