Answer:
2.06 m/s
Explanation:
From the law of conservation of linear momentum, the sum of momentum before and after collision are equal. Considering this case where we have frictionless surface, no momentum is lost in the process.
Momentum before collision
Momentum is given by p=mv where m and v represent mass. The initial sum of momentum will be 9v+(27*0.5)=9v+13.5
Momentum after collision
The momentum after collision will be given by (9+27)*0.9=32.4
Relating the two then 9v+13.5=32.4
9v=18.5
V=2.055555555555555555555555555555555555555 m/s
Rounded off, v is approximately 2.06 m/s
Answer:

Explanation:
The formula for kinetic energy is:

We can plug in the given values into the equation:



So for a minute lets ignore the 880 km/h. If it took 4 hours and she flew at 600 km/h 600*4=2400. Now lets Look at the 880 bit. If it took 4 hours and she where to fly at 880 it would've been 880*4=3520. Lets do 2400-600=1800, now we've got the 600 kmh bit done. Now lets see if you fly 880 km/h for one hour then you add 1800+880=2680.
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Answer:
The magnitude of the second charge is
or 
Explanation:
The work done in bringing a charged particle from one point to another in the presence of some electric field is equal to the change in the electric potential energy of the charge in moving from one point to another.
The electric potential energy of some charge
at a point in the electric field of another charge
is given by the product of the amount of charge
and electric potential at that point due to the charge
.

The electric potential at that point is given by

where
is the Coulomb's constant.
Therefore,

Now, We have given two charges
and
, whose value is to be found.
When the two charges are infinitely dar apart, the electric potential energy of the system is given by

When the coordinates of position of the two charges are

The distance between the two charges is given by

The electric potential energy of the charges in this configuration is given by

The change in the electric potential energy of the system is equal to the work done to bring the system from inifinitely far apart position to given configuration.
Therefore,

Answer:
The string will break with a speed of 20 m/s.
Explanation:
It is given that,
Tension at which the string just breaks, T = 400 N
Mass of the stone, m = 10 kg
Radius of the circle, r = 10 m
We need to find the speed at which the string will break. The boy continuously increases the speed of the stone. The tension acting on the stone is equal to the centripetal force. It is a force that acts towards the center of circle. It is given by :



v = 20 m/s
So, the string will break with a speed of 20 m/s. Hence, this is the required solution.