The speed downwards is 7 + (3*9.8)
7+ 29.4 = 36.4 m/s
Answer:
0.71 J
Explanation:
320 g = 0.32 kg
According to law of energy conservation, the energy loss to external environment (air, ground) can be credited to the change in mechanical energy of the ball.
As the ball was dropped at H = 2 m above the ground then later reaches its maximum height at h = 1.2m, tts instant speed at those 2 points must be 0. So the kinetic energy at those points are 0 as well. The change in mechanical energy is the change in potential energy.
Let g = 9.81 m/s2

Since 1.8J of 2.51 J is due to work by air resistance, the rest of the energy (2.51 - 1.8 = 0.71 J) is would go to heating in the ground and ball when it bounces.
What substances? Depends on their density, the lower density floats on top. For example, oil floats on top of water
Answer:
Z
Explanation:
The figure represented the ray diagrams produced by a convex (converging lens). The image will appear at the point where the purple ray and the orange ray meet, so at point Z.
As we see from the picture, the image will be:
- Real (because it is behind the lens, and it can be projected on a screen)
- Inverted (the image is upside down)
- Larger than the object (we can see it by noticing that the distance between the point of intersection purple-orange ray and the axis is larger than the size of the object)
A) Vt = Vo - gt
= 0 - 9.8 . 2
= - 19.6 m/sec (acting downward)
b) ∆y = Vt^2 - Vo^2 / 2g
= (-19.6)^2 - 0 / 19.6 = 19.6 meters