Explanation:
<h3>
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.
Answer:
2. The total initial angular momentum is non-zero and total angular momentum is conserved.
Explanation:
Let the mass of the boy be m and v be his velocity . His linear momentum
p = mv , If R be the radius of the circular path of merry go round . When the boy jumps on the merry gold round , he adds an angular momentum to the system .
Angular momentum of the boy with respect to the center of merry go round
L = r x p = r p sin90.
= r p
= m v r
This is the initial angular momentum of the system of boy and merry go round .
Total final angular momentum of the system will also be equal to initial angular momentum , according to law of conservation of angular momentum , since no external torque is acting on the system.
Answer:
i think D
hope this helps
let me know if i'm wrong i will change the answer
Explanation:
B.
A star is not a vector quantity.
Neither is temperature.
Answer:
σ = 1.52 10⁻¹² 1 /Ω m
Explanation:
The current density is linear in the atmosphere, so it complies with Ohm's law
J = σ E
Where J is the current density, sigma is the electrical inductance and E is the electric field
σ = J / E
σ = 7.3 10⁻¹³ / 48
σ = 1.52 10⁻¹² A / V 1 / m
σ = 1.52 10⁻¹² 1 /Ω m