Given that,
Mass of a baseball, m = 0.2 kg
Initial speed of a baseball, u = 30 m/s
Force produced by a bat, F = 2000 N
Final speed of a baseball, v = -50 (negative for opposite direction)
To find,
For how long was the ball in contact with the bat?
Solution,
Let for t seconds the ball is in contact with the bat. The net force acting on the ball is given by :
So, the ball is contact with the bat for 8 ms.
My guess would be because the gravity from the Earth's core is constantly pulling the ball towards the ground. It's like the moon. Why doesn't the moon just float away in space? Because Earth's gravitational pull keeps it rotating around it. Therefore, the ball will always be pulled towards the core which keeps it from from rolling forever due to friction. But i may be wrong, even though this a quite a good answer, hope it is right!
Answer:
2) τ = F x torque increases, 3) troque decreases,
4) man approaches the pivot and the child must move away
5) Σ τ = 0
Explanation:
2) when the man moves away from the pivot his torque increases significantly, since his distance increases
τ = F x
τ = m g x
therefore the system rotates faster
3) when the child approaches the pivot, his troque decreases, because the distance decreases
τ = f x
therefore the system must spin slower
4) If we place the man and the child on the side of a scale, the movement must be the man approaches the pivot and the child must move away, so that the torque is the same and the system can reach a balance
5) the rotational equilibrium expression
Σ τ = 0
is the one that describes the equilibrium of a system with several forces
Answer:
1 False. Atoms can be divided, see case of radioactive materials
Explanation:
Dalton's theory says that matter is made up of very small particles called atoms that are indivisible and cannot be destroyed, chemical compounds are made up of atoms.
With this statement, we can review the proposals,
1 False. Atoms can be divided, see case of radioactive materials
2 True. Chemical reactions are performed by atoms.
3 True. This statement remains unchanged.
4 True. The compound or molecules are formed by atoms