5a 30 kg girl and a 25 kg boy face each other on friction -free roller blades . the girl pushes the boy ,who moves away at a speed of 1.0 m/s . the girls speed is how many m/s /
m1v1 = m2v2
(30kg)(v1)=(25kg)(1.0m/s)
solve for v1
0.45
To find the girl's speed, we can use the principle of conservation of momentum.
The principle of conservation of momentum states that the total momentum before an event is equal to the total momentum after the event, assuming there are no external forces acting on the system.
In this case, the girl pushes the boy, causing him to move away. Since there are no external forces mentioned in the problem, the momentum before the push is equal to the momentum after the push.
The momentum of an object can be calculated by multiplying its mass by its velocity.
Let's denote the girl's speed as v (in m/s). Using the principle of conservation of momentum, we can set up the following equation:
(mass of girl) x (speed of girl) = (mass of boy) x (speed of boy)
Substituting the given values:
(30 kg) x v = (25 kg) x (1.0 m/s)
Now, we can solve for v by isolating it on one side of the equation:
v = (25 kg) x (1.0 m/s) / (30 kg)
v = 25/30 m/s
Simplifying the fraction:
v = 5/6 m/s
Therefore, the girl's speed is 5/6 m/s.