Answer:
B.
It will be greater than 10 J.
Explanation:
The total mechanical energy of an object is the sum of its potential energy (PE) and its kinetic energy (KE):
E = PE + KE
According to the law of conservation of energy, when there are no frictional forces on an object, its mechanical energy is conserved.
The potential energy PE is the energy due to the position of the object: the highest the object above the ground, the highest its PE.
The kinetic energy KE is the energy due to the motion of the object: the highest its speed, the largest its KE.
Here at the beginning, when it is at the top of the roof, the baseball has:
PE = 120 J
KE = 10 J
So the total energy is
E = 120 + 10 = 130 J
As the ball falls down, its potential energy decreases, since its height decreases; as a result, since the total energy must remain constant, its kinetic energy increases (as its speed increases).
Therefore, when the ball reaches the ground, its kinetic energy must be greater than 10 J.
Answer:
According to your question although I think an object undergoing uniform circular motion is moving with a constant speed. Nevertheless, it is accelerating due to its change in direction. The direction of the acceleration is inwards,therefore a force perpendicular to an objects velocity change the direction of the velocity but not its magnitude.
The initial momentum of the system can be expressed as,
The final momentum of the system can be given as,
According to conservation of momentum,
Plug in the known expressions,
Initially, the second mass move towards the first mass therefore the initial speed of second mass will be taken as negative and the recoil velocity of first mass is also taken as negative.
Plug in the known values,
Thus, the final velocity of second mass is 2.99 m/s.
Answer:
towards west
Explanation:
As we know that the speed of the blue car as appear to the bicycle rider is given as
towards west
also it is given that bicycle is moving at speed of 10 km/h towards East
so here we have
so we have
towards west
now speed of the red car is given as 15 km/h towards west
so here the relative speed of blue car with respect to red car is given as
towards west