Answer:
The ball will reach the ground in 0.8s
Option C
Explanation:
Given:
- Takes t = 0.8 s for ball to reach ground when thrown horizontal from top of a building.
Find:
If it had been thrown with twice the speed in the same direction, it would have hit the ground in how many second.
Solution:
- We know that the amount of time taken to hit the ground is determined by the vertical distance i.e height at which it is thrown. The displacement of ball from top is given by:
S_y = S_o + V_i,y*t + 0.5*g*t^2
- We know that the S_o = height of the building.
We also know that the ball os thrown horizontally; hence, y-component of initial velocity is zero. V_y,i = 0
0 = h + 0 + 0.5*g*t^2
- Hence, the time taken t is:
t = sqrt ( 2h / g)
- The time taken to reach the ground is independent of the initial speed. Hence, the ball will reach the ground in 0.8s .
Answer:
Refraction
Explanation:
A pencil bends when it enters the water media due to the phenomenon of refraction.
- Refraction is one of the properties of waves.
- Refraction of light occurs which it crosses from a region having different density values.
- Water is denser than air.
- As light moves from air to wave it becomes refracted
Answer:
c) nonzero, directed toward the spaceship
Explanation:
As we know that net gravitational force due to spherical shell inside all its points will always be zero
So if planet is a spherical shell then inside the planet net gravitational force is zero on the people living in it
So when massive spaceship land on the surface of planet then the gravitational force of the spaceship is experienced by the people inside the shell
So here the gravitational force on the people is nonzero and it is towards the spaceship which landed on the surface of planet
