2m/s because the hockey puck is traveling at a constant speed ( acceleration is 0 ). Unless something acts on the hockey puck it will travel 2 m/s forever.
I think true. I'm pretty sure, but check w/ others too.
Assuming this coin is on earth and that it wasn’t dropped forcefully:
Use the formula d = 1/2at^2. Rewriting using a=g and solving for height h gets us h = 1/2(9.8)t^2.
In this case that would get that the change in height h is 0.5(9.8)(0.3^2) = 0.441 m.
To solve this problem we will apply the concepts related to the Electrostatic Force given by Coulomb's law. This force can be mathematically described as
Here
k = Coulomb's Constant
Charge of each object
d = Distance
Our values are given as,
d = 1 m
a) The electric force on charge 
is
Force is positive i.e. repulsive
b) As the force exerted on will be equal to that act on 
,
Force is positive i.e. repulsive
c) If 
, a negative sign will be introduced into the expression above i.e.
Force is negative i.e. attractive
