Answer:
the velocity in all the cases will be same.
Explanation:
given,
girl throws a stone from the bridge
air is friction less
we have to find from the given cases in which case the velocity of stone will be greatest.
According to Work energy theorem work done by the sum of all the force is equal to kinetic energy.
As the air is frictionless hence the speed depend upon the height from which the stone is thrown.
height in all the cases is same.
so, the velocity in all the cases will be same.
Answer:
the answer is B
Explanation:
the law states that for every action there is an equal and opposite reaction. action and reaction forces always act on two two different bodies and therefore THEY ALWAYS EXIST IN PAIRS.
Answer:
C. The floor pushing back against the foot
Explanation:
As you increase the temperature, the matter begins to expand. Due to this, the distance between matter particles decreases and they are no more compact. Hence, density decreases.
Answer:
17.6 N
Explanation:
The force exerted by the punter on the football is equal to the rate of change of momentum of the football:
where
is the change in momentum of the football
is the time elapsed
The change in momentum can be written as
where
m = 0.55 kg is the mass of the football
u = 0 is the initial velocity (the ball starts from rest)
v = 8.0 m/s is the final velocity
Combining the two equations and substituting the values, we find the force exerted on the ball: