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:
He needs 1.53 seconds to stop the car.
Explanation:
Let the mass of the car is 1500 kg
Speed of the car, v = 20.5 m/s
He will not push the car with a force greater than, 
The impulse delivered to the object is given by the change in momentum as :

So, he needs 1.53 seconds to stop the car. Hence, this is the required solution.
Answer:
75k
Explanation:
You can see solution in the picture
Answer:
0.12959085 J
Explanation:
k = Coulomb constant = 
q = Charge = 1.55 μC
d = Distance between charge = 0.5 m
Electric potential energy is given by

In this system with three charges which are equidistant from each other


The potential energy of the system is 0.12959085 J
Answer:
C. HertzPrung Russel Diagram
Explanation:
The Hertzsprung–Russell diagram, or H–R diagram, is a plot of stellar luminosity against surface temperature. Most stars lie on the main sequence, which extends diagonally across the H–R diagram from high temperature and high luminosity to low temperature and low luminosity.