Answer:
-0.912 m/s
Explanation:
When the package is thrown out, momentum is conserved. The total momentum after is the same as the total momentum before, which is 0, since the boat was initially at rest.
where 
are the mass of the child, the boat and the package, respectively. 
are the velocity of the package and the boat after throwing.
Answer:
B = 0.75 T
Explanation:
As we know that the force on a moving charge in magnetic field is given by the formula
here we have
here we know that
now from above equation we have
The energy stored by a system of capacitors is given by
where Ceq is the equivalent capacitance of the system, and V is the voltage applied.
In the formula, we can see there is a direct proportionality between U and C. This means that if we want to increase the energy stored by 4 times, we have to increase C by 4 times, if we keep the same voltage.
Calling
the capacitance of the original capacitor, we can solve the problem by asking that, adding a new capacitor with
, the new equivalent capacitance of the system
must be equal to
. If we add the new capacitance X in parallel, the equivalent capacitance of the new system is the sum of the two capacitance
and since Ceq must be equal to 4 C1, we can write
from which we find
They are slowed down.
even air is a medium and will slow down waves (slightly) compared to a vacuum/ space
if the wave hits the medium at an angle it can be 'bent' (refracted) like light through a glass prism
