Explanation:
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Need to FinD :</h3>
- The velocity of the ball with strikes the ground.
- The time of the ball after which it strikes the ground.
We know that,
- The ball is dropped from the height of 30 m as stated in the question. Therefore, it will have a initial velocity of 0 m/s. The distance travelled by the ball will be 30 metres as the distance travelled by the ball is equal to the height of the tower and that is 30 metres.
So, by using the third equation of motion, we will find out the final velocity of the ball.
Therefore,
∴ Hence, the required final velocity of the ball with which it strikes the ground is 24.5 m/s. Since, we know that the initial velocity of the ball is 0 m/s and the acceleration of the ball is 10 m/s². So, by using the first equation of motion, we will find out the time of the ball after which it stikes the ground.
Therefore,
∴ Hence, the required time of the ball after which it strikes the ground is 2.45 seconds.
We can ignore all that business about resting on the rock and
rolling down part of the way and then resting on the moss.
Its potential energy right now doesn't depend on what happened
to it yesterday. We don't care.
All we care about is that we're walking along in the park and we
notice a 1.5kg rock lying in moss 10 meters above the ground.
Gravitational potential energy
= (mass) · (gravity) · (height)
= (1.5 kg) · (9.8 N/kg) · (10 m)
= 147 (kg · N · m / kg)
= 147 joules
tritium = hydrogen with 2 neutrons.
deuterium= H with one neutron
I think since applied force and displacement are perpendicular to each other, then the work done is zero. I hope this helps.